The clinical meaning of an NNT is subject to interpretation. For example, an NNT of 100 over five years to avoid one clinical event might be seen by some doctors as a health benefit, whereas others will consider the benefit as only moderate or even slight. References. Laupacis A, Sackett DL, Roberts RS However, many authors still use only one method. Adding an estimate of the NNT to gain, on average, one additional improvement, may aid interpretation of trials with continuous outcomes that are not intuitively understandable to patients, clinicians, and purchasers; few authors do this Patient aims to help the world proactively manage its healthcare, supplying evidence-based information on a wide range of medical and health topics to patients and health professionals.© Patient Platform Limited. Registered in England and Wales. All rights reserved. Patient does not provide medical advice, diagnosis or treatment. For the DCCT data, NNT = 1/.068 = 14.7. Thus, for every 15 patients treated with intensive therapy, one case of neuropathy would be prevented. The NNT concept has been gaining in popularity because of its simplicity to compute and its ease of interpretion
Additional Info. In addition to the unrivalled feature set, NNT Change Tracker is the most certified and integrated solution of its type. NNT integrates with all leading ITSM vendors to provide the most sophisticated closed loop intelligent change control system as well as integrations with all leading SIEM solutions to assist with correlation and context of events as well as invaluable. The concept of number needed to treat (NNT) was introduced in the medical literature by Laupacis et al. in 1988 [].NNT is an absolute effect measure which is interpreted as the number of patients needed to be treated with one therapy versus another for one patient to encounter an additional outcome of interest within a defined period of time [1, 2]
Abstract: The number needed to treat (NNT) is widely used to present the results of clinical trials. However, incorrect calculations, misuse in specific study situations and misleading interpretation of NNTs are not uncommon in practice, for example in the case of non-significant results or in the situation of survival time data Number Needed to Treat (NNT): A tool to analyze harms and benefits. Attacking the person, instead of the idea or the interpretation, is neither acceptable nor helpful.. NNT (number needed to treat) = 1 / ARR. Examples. RR of 0.8 means an RRR of 20% (meaning a 20% reduction in the relative risk of the specified outcome in the treatment group compared with the control group). RRR is usually constant across a range of absolute risks. But the ARR is higher and the NNT lower in people with higher absolute risks relief compared with placebo (NNT=4.4; 95% CI 2.4 to 24.4 and 3.8; 95% CI 2.5 to 7.3, respec-tively). For SSc interventions, none were shown to be efficacious in improving Raynaud's phenomenon because the 95% CI of the NNT was infinite. Conclusions: The NNT and NNH are helpful for clinicians, enabling them to translate the results fro The number needed to treat (NNT) is a useful way for clinicans to describe the benefit or harm of a treatment as well as the costs involved. When interpreting the NNT it is essential to use the NNT in a clinically equivalent and appropriate setting
Given baseline risk information for a hypothetical disease, plus RR, AR, NNT, or combination. Correct interpretation: 25% for NNT compared with 75% for the non-NNT. Chao (2003), also reported by Studts (2005): 203 pre-clinical medical students, USA. RR, AR, NNT, absolute survival benefit. Round 1 given 1; round 2 given all 4 Svend's -syntax- allows -if- and -in-, but the program ignores them. In addition, I suggest adding a -version- statement and some rounding in the display • So the number needed to treat (NNT) is 1/0.03 or 33 • Interpretation: in the setting of an acute MI, one would need to treat 33 patients with thrombolyti
The Number Needed to Treat (NNT) is the number of patients you need to treat to prevent one additional bad outcome (death, stroke, etc.). For example, if a drug has an NNT of 5, it means you have to treat 5 people with the drug to prevent one additional bad outcome. More detailed discussion of the nature of the NNT measure can be found in the. The choice of the appropriate population over which the averaging of risk differences is performed depends on the research question and the study design [17,18]. In the context of cohort studies investigating the effect of exposures, averaging is performed separately over the unexposed or the exposed person leading to two different NNT measures [13,17]. In the first case the effect of allocating the exposure to unexposed persons (NNE) and in the second the effect of removing the exposure from exposed persons (EIN) is described. In the case of equal distributions of the covariates NNE and EIN are identical. However, usually the distributions of the covariates are different between the unexposed and exposed persons in the context of cohort studies leading to different values for NNE and EIN. Through the looking glass: understanding non-inferiority. The logical interpretation of a meta-analysis using either of these methods is not that the true effect of the treatment is the same in all situations, but rather that the overall estimate obtained from a meta-analysis is the best estimate of the treatment effect, averaged over all. Hutton JL; Number needed to treat and number needed to harm are not the best way to report and assess the results of randomised clinical trials. Br J Haematol. 2009 Jun146(1):27-30. Epub 2009 Apr 27.
Professional Reference articles are designed for health professionals to use. They are written by UK doctors and based on research evidence, UK and European Guidelines. You may find the Calculating absolute risk and relative risk article more useful, or one of our other health articles. Many people, as shown in the literature, misinterpret the NNT. One mis-interpretation is to treat the NNT as a within-person measure (e.g., I will do 10 times better if I use treatment A). While the NNT may make some sense for acute conditions, what if we are talking about a chronic condition (e.g., hypertension and risk of stroke) Interpretation of NNT values requires data on the magnitude of baseline risk, the comparator group, the duration of therapy, and the end points evaluated. 5 In primary prevention among those with overt hyperlipidemia, 5-year NNT values ranging between 40 and 70 have been observed in the AFCAPS/TexCAPS trial of lovastatin and in the WOSCOPS.
In summary, depending on the research question and the study design, different adjusted NNT measures should be applied. In the context of cohort studies NNE describes the average effect of allocating an exposure to unexposed persons, whereas EIN describes the average effect of removing the exposure from exposed persons. In the context of clinical trails (randomized or non-randomized) NNT describes the average treatment effect in the whole population of patients. Clinical trials are the foundations of evidence-based treatments. Trials must be critically appraised to confirm the validity of conclusions. Further analysis is required to show if the results from the trial, where patients are carefully selected and followed up in detail, can be extrapolated to other patients and different settings Neonatal ECG Interpretation . fl. 3 . Cardiac Rhythms and Arrhythmias . 17. Figure 3-1 . fl. Normal sinus rhythm. Figure 3-2 . fl. Sinus bradycardia. Figure 3-3 . fl. Lengthening of RR interval with slowing heart rate. Courtesy of: NICU INK Book Publishers. From: Pilcher J. 2016. Pocket Guide to Neonatal ECG Interpretation, 3rd ed.
What does NNT stand for? List of 54 NNT definitions. Updated April 2020. Top NNT abbreviation meaning: Number Needed To Trea The graphical representation of NNTs from NMA is crucial to ease interpretation of results. We present six graphical approaches for NNT from NMA and discuss their properties. Impact: A NNT may be presented in a bar plot, Cates plot or forest plot for a single outcome, and a bubble plot, scatterplot or rank-heat plot for ≥2 outcome
Read 4 answers by scientists with 2 recommendations from their colleagues to the question asked by Fekadu Mazengia Alemu on Mar 1, 201 NNT and the Importance of Its Value What is the importance of the value of the NNT? Obviously, the smaller the NNT, the greater the unique contribution of the drug toward the outcome. So, if the NNT for a drug is 4, it means that just 4 patients need to be treated with that drug for 1 additional patient to respond Attrition from olanzapine versus placebo studies was >50% by six weeks, leaving interpretation of results problematic. Olanzapine appeared superior to placebo at six weeks for the outcome of 'no important clinical response' (any dose, 2 RCTs n=418, RR 0.88 CI 0.8 to 0.1, NNT 8 CI 5 to 27) An NNT of 20 is interpreted as that a clinician will need to treat 20 patients in order to prevent one adverse outcome 4. The authors interpret the NNT as the number of people who must be treated in order that one adverse event is prevented by the treatment at issue NNT = Number of patients that must be given the experimental treatment for the duration of the study to prevent a single outcome e.g. death or other measurable variable. Formula: NNT = 1/ARR. The inverse of the absolute risk reduction, NNT, is an important measure in pharmacoeconomics. If a clinical endpoint is devastating enough (e.g. death.
theNNT, Explained. The NNT Video Introduction The Basic Idea. There is a way of understanding how much modern medicine has to offer individual patients. It is a simple statistical concept called the Number-Needed-to-Treat, or for short the 'NNT'. The NNT offers a measurement of the impact of a medicine or therapy by estimating the. The number needed to treat (NNT) is a useful way of reporting the results of randomised controlled trials.1 In a trial comparing a new treatment with a standard one, the number needed to treat is. Clinicians, providers and guideline panels use absolute effects to weigh the advantages and downsides of treatment alternatives. Relative measures have the potential to mislead readers. However, little is known about the reporting of absolute measures in systematic reviews. The objectives of our study are to determine the proportion of systematic reviews that report absolute measures of effect.
In summary, in data situations where the effects of covariates play an important role, the application of NNTs with adjustment for covariates is required to present study results in terms of NNTs. To describe treatment effects with a population perspective the new impact numbers can be used, however, methods to estimate adjusted impact numbers have to be developed. National Center for Biotechnology Information, U.S. National Library of Medicine 8600 Rockville Pike, Bethesda MD, 20894 USA
Interpretation of Clinical Results. STUDY. Flashcards. Learn. Write. Spell. Test. PLAY. Match. Gravity. Created by. christine_hassell. From a clinical stand point, which is more significant, a high or low ES and NNT? A sample with a low ES and low NNT may be more significant than a sample with a high ES and high NNT from a clinical. Number Needed to Treat Menu location: Analysis_Clinical Epidemiology_Number Needed to Treat. This function gives relative risk, relative risk reduction, absolute risk reduction (risk difference) and number needed to treat (NNT) with exact or near-exact confidence intervals
The HR for death from any cause in our meta-analysis of GLP-1 receptor agonist trials was 0·88 (95% CI 0·83-0·95) and the NNT was 113 (80-271); in the SGLT2 inhibitor meta-analysis, the corresponding HR was 0·85 (0·78-0·93) and the corresponding NNT was 101 (69-216) Risk, Risk ratio, Odds Ratio, NNT NNH. STUDY. Flashcards. Learn. Write. Spell. Test. PLAY. Match. Gravity. Created by. satishtray. Terms in this set (20) Hazard. Is any source of potential damage, harm Basically, it can cause harm or adverse effects Sometimes it is referred to as being the actual harm or the health effect it caused rather than.
We now consider how adjusted NNTs can be used to describe the absolute treatment effect of OHP adequately. If we are interested in the overall average effect of OHP in the population of MS positive children taking the distribution of the caretakers' occupation into account an adequate approach is given by an adaptation of the ARD approach allowing a covariate×treatment interaction, here the interaction between occupation and OHP. This approach yields the result NNTB = 12.2 (95% CI: 6.2 to 331.2, p = 0.042), i.e. a statistically significant overall beneficial treatment effect. This result means that, on average, 12 to 13 MS positive children from a population with a distribution of occupation as in the considered sample are needed to receive the OHP to have one case of dental caries at age 5 years less compared to the traditional program. Due to estimation uncertainty NNT may also lie between 6 and 331 MS positive children receiving OHP to prevent dental caries at age 5 years in one additional child compared to the traditional program.By means of multiple logistic regression containing treatment, occupation and the corresponding interaction term it can be shown that there is a statistically significant interaction between treatment and occupation (p < 0.001). Therefore, the effect of OHP is different between children from white and blue collar families. Nevertheless, the overall average treatment effect is of interest accounting for the distribution of the caretakers' occupation. TERMS AND CONDITIONS OF SALE These are the terms and conditions upon which each subsidiary of The Workwear Group Holding Pty Ltd or their respective Agents, sell and quote for the sale of goods. 1. DEFINITIONS AND INTERPRETATION 1.1 Definitions. In these terms and conditions, unless the context otherwise requires Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Patient Platform Limited has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions. OBJECTIVE: To define four measures of association relative risk (RR), absolute risk reduction (ARR), relative risk reduction (RRR), and number-needed-to-treat (NNT), demonstrate the method of calculating these values, and discuss the clinical relevance of each value. DATA SOURCES: MEDLINE 1991 to present and bibliographies of pertinent articles
Abstract. Background Meta-analyses summarize the magnitude of treatment effect using a number of measures of association, including the odds ratio (OR), risk ratio (RR), risk difference (RD) and/or number needed to treat (NNT). In applying the results of a meta-analysis to individual patients, some textbooks of evidence-based medicine advocate individualizing NNT, based on the RR and the. 1Department of Medical Biometry, Institute for Quality and Efficiency in Health Care (IQWiG), Cologne, GermanyThe number needed to treat (NNT) is the number of patients who need a specific treatment to prevent one additional bad outcome (eg, myocardial infarction, stroke). The NNT specifies the treatment, its duration and the adverse outcome being prevented. Therefore, if a drug has an NNT of 10, it means you have to treat 10 people with the drug to prevent one additional bad outcome. The NNT would then be 3.3. In all cases the NNT is rounded up, so in this case it would be 4. In a perfect world an intervention would have an NNT of 1 meaning that everyone would experience the benefit of the drug. Unfortunately, an NNT of 1 is very rare, but the smaller the NNT, the better the intervention
The number needed to treat: problems describing non-significant results The number needed to treat (NNT) and its counterpart, the number needed to harm (NNH), are commonly used measures of effect in studies of mental health treatments. The NNT is an absolute measure, which conveys a more direct and intuitiv The complete blood count (CBC) is one of the most commonly ordered blood tests. The complete blood count is the calculation of the cellular (formed elements) of blood. Special machines that analyze the different components of blood in less than a minute generally determine these calculations
The NNT analysis find how many patients need to be treated in order to prevent one event happening. The same analysis can be made for side effects, resulting in a NNH (Number Needed to Harm). Fill in the blue boxes with the results of a controled study, and the results of various statistical analyses are given in the orange output boxes Stratimagic automated classification methods are used in all types of geological settings, from drilling risk analysis (geohazards) up to 4D projects. As Stratimagic's primary classification scheme, NNT creates a proven foundation for recovering hierarchal structure from seismic data. The result is more meaningful geologic interpretation Historically, the use of NNT was based on dichotomous efficacy data and reported in trials in which T was better than C. In a clinical trial of MI (see example in the Introduction), an NNT of 304 is interpreted as indicating that 304 patients would need to be treated, on average, with the drug to prevent one MI. Adverse event (AE) data are collected in such trials and, by definition. If the two groups have the same n, then the effect size is simply calculated by subtracting the means and dividing the result by the pooled standard deviation.The resulting effect size is called d Cohen and it represents the difference between the groups in terms of their common standard deviation. It is used f. e. for calculating the effect for pre-post comparisons in single groups RELATIVE RISK, ODDS RATIO, ATTRIBUTABLE RISK AND NUMBER NEEDED TO TREAT An improved version of this article is now available in Third Edition (2012) of the book Medical Biostatistics (CRC Press, New York) by Abhaya Indrayan Adapted from Basic Methods of Medical Research, Third Editio
The intervention was targeted to mutans streptococci (MS) positive children. Only MS positive children are considered in the following for simplification. A complete analysis of all data would require the consideration of additional covariates. After triplication, n=531 MS positive "children" were obtained, nIG=267 in the intervention (OHP) and nCG=264 in the control group (traditional program). An important covariate in this example is given by the occupation of caretakers (blue collar vs. white collar). The results for the main outcome dental caries with stratification for occupation are given in Table 11. Interpretation of number needed to treat, number needed to harm, and likelihood to be helped or harmed. success rate difference, attributable risk and number needed to treat (NNT). Of all of these measures, NNT is arguably the most clinically intuitive and helps relate effect size difference back to real-world concerns of clinical practice. The effects of statins in the elderly are better informed by absolute effects and the number needed to evaluate the benefit to harm balance. Such an approach enables patients to make more informative choices. Statins have proved to be a controversial topic. Thirty years after their approval, uncertainties remain about the benefit to harm balance in primary prevention of cardiovascular events. In applications of NNTs in biomedical research a frequent problem is given by the fact that – although adjusted ORs are estimated and presented – crude naive NNTs based upon simple standard methods are calculated [13]. If we neglect the occupation of caretakers and estimate the NNT based upon the 2×2 table of white and blue collar caretakers together by means of standard methods the result NNT = 13.9 is obtained. However, the chi-square test yields a not significant result (p = 0.085) and the confidence region for NNT includes infinity (i.e. the zero effect). This result can be presented as NNTB = 13.9 (95% CI: NNTB 6.5 to ∞ to NNTH 103.8), where NNTB and NNTH mean number needed to treat for one patient to benefit or to be harmed, respectively, to indicate the direction of the effect [24,25]. However, the crude NNT estimation is inefficient and potentially biased because the covariate occupation is not taken into account. Application and Interpretation. The choice of the appropriate population over which the averaging of risk differences is performed depends on the research question and the study design [17,18].In the context of cohort studies investigating the effect of exposures, averaging is performed separately over the unexposed or the exposed person leading to two different NNT measures [13,17]
The preventive effect of a risk-based oral health program (OHP) in comparison with a traditional program on occurrence of dental caries was evaluated in a prospective controlled study of Finnish children followed from 18 months to 5 years of age [22]. The study reported a protective effect of OHP in white-collar families and NNTs were applied to present study results. The data set contains an interesting covariate×treatment effect. Unfortunately, the study power was too low to show a significant overall average treatment effect. For illustrative purposes the original data were tripled to increase study power. Although based upon real data, the following results are hypothetical because the amount of data was artificially increased.Sedgwick P; Measuring the benefit of treatment: number needed to treat. BMJ. 2015 Apr 27350:h2206. doi: 10.1136/bmj.h2206. The NNT is the inverse of the risk difference and indicates the number of patients required to be treated to avoid one additional outcome event. Risk difference and NNT are absolute measures of effect. Relative risk (RR) is a relative measure and is the ratio of the risk in the exposed group to that in the unexposed group
Risk Reduction Calculator. Given information about the probability of an outcome under control and experimental treatments, this calculator produces measures of risk increase/decrease and number needed to treat or harm, including confidence intervals These results are obtained by applying simple standard methods which are appropriate in RCTs with individual randomization, two parallel groups, fixed follow-up time, binary outcome and sufficient sample size. In other situations in which clustered data, time-to-event outcomes or confounding play a role, more complex methods are required to estimate NNTs appropriately. In the following, we focus attention on application of adjusted NNTs which allow the consideration of important confounders in epidemiology as well as accounting for balanced covariates and covariate× treatment interactions in RCTs. Number Needed to Treat (NNT) is the number of patients that must be treated over a given period of time to prevent one adverse outcome. NNT = 1/ARR ; Odds Ratio (OR) The ratio of the odds of having the target disorder in the experimental group relative to the odds in favor of having the target disorder in the control group (in cohort studies or.
Latent TB. The central challenge of treatment for LTBI is identifying those with the highest risk of progression. Since only approximately 5% of TST-positive TB contacts progress to active TB within 2-5 years of exposure,4 the number of TST-positive contacts requiring treatment to prevent one case of active TB (number needed to treat, NNT) is about 20 NNT in Periodontal Research. The NNT to avoid one additional site with progressive disease under the intervention compared with the control arm has been described as a useful summary of the clinical benefit of a treatment. 1, 2 Greenstein and Nunn 3 have presented details about the calculation and interpretation of NNT in periodontal research, and the meta-analysis literature 4 has discussed.
The short-term effect of a school-based educational program on oral cleanliness was evaluated by means of a cluster randomized trial and described in terms of NNT [20]. In short, 15 year old students at public schools in Teheran, Iran, were cluster-randomized to the control group (n=130) or one of two oral health intervention groups, a leaflet group (n=148) and a videotape group (n=139) and outcomes were evaluated after 12 weeks. For illustration, we consider only the control and videotape groups and the outcome improvement in oral cleanliness (IOC). For statistical analyses paired and unpaired t-tests and the chi-square test were used; NNT was calculated as inverse of the absolute risk reduction. The result concerning IOC was presented as "… improvement of oral cleanliness occurred … in 37% (p < 0.001) in the videotape group, and in 10% in the control group … NNT was … three in the videotape group." Additionally, the proportions and NNTs (both rounded to integers) were given in a table separately for boys (NNT = 2) and girls (NNT = 10). Relative Risk and Odds Ratios: Examples Calculating Relative Risk Calculating Relative Risk Imagine that the incidence of gun violence is compared in two cities, one with relaxed gun laws (A), the other with strict gun laws (B). In the city with relaxed gun laws, there were 50 shootings in Number Needed to Treat (NNT) represents the number of patients over a given time period that one would need to treat to achieve one additional study endpoint. As an example, in the PROSEVA trial of patients with severe ARDS , prone positioning decreased 28-day all-cause mortality compared to supine positioning (16% vs. 32.8%) with a NNT of 6 2 thoughts on Number Needed to Treat (NNT) website and Statin Drugs Julie henderson October 27, 2013 at 9:35 pm. My brother was diagnosed with chronic fatigue. Last week his new primary care physician took him off of statins. He's starting to feel better already EVIDENCE-BASED MEDICINE (EBM) Overvi ew: Not s on Validity, Precision & Contextualization of Results NNT, NNH, a CI that includes zero means possibility of no difference between tx. interpretation as one endpoint may be the primary driver. {e.g. In DREAM, outcome of diabetes diagnosi
The number needed to treat (NNT) and its counterpart, the number needed to harm (NNH), are commonly used measures of effect in studies of mental health treatments. The NNT is an absolute measure, which conveys a more direct and intuitive impression of the effect on an individual than the absolute risk reduction (ARR). To illustrate this, consider an imaginary trial comparing the effects of. Interpretation of FHR Tracings A concern with continuous EFM is the lack of (NNT = 661), but not the occurrence of cerebral palsy. Continuous EFM increased cesarean delivery rates overall (NNH. Definition of number needed to harm in the Definitions.net dictionary. Meaning of number needed to harm. What does number needed to harm mean? Information and translations of number needed to harm in the most comprehensive dictionary definitions resource on the web In postmenopausal women, a 10-mg daily dose of alendronate is effective for secondary (number needed to treat [NNT] = 16) and primary (NNT = 50) prevention of vertebral fractures. It is also.
The International Knockout Mouse Consortium (IKMC) introduces its targeted constructs into C57BL/6N embryonic stem cells. However, breeding with a Cre-recombinase and/or Flp-recombinase mouse is required for the generation of a null allele with the IKMC cassette. Many recombinase strains are in the C57BL/6J background, resulting in knockout animals on a mixed strain background Number needed to harm is similar to number Number needed to treat (NNT); While NNH is a measure of harm or adverse effects, NNT is a measure of how many patients needed to be treated in order for one to benefit. Together, these statistics help physicians decide on courses of treatment. Lower NNT and higher NNH treatments are preferred over.
It is possible to convert Cohen's d into a version of NNT that is invariant to the event rate of the control group. The interested reader should look at Furukawa and Leucht (2011) where a convincing argument is given to why this complicates the interpretation of NNT. R code to calculate NNT from Cohen's Number needed to treat (NNT) How effective is a clinical treatment? Because many people find it hard to think about small fractions, these kind of data are better understood when converted to the Number Needed to Treat or NNT. Enter the number of patients in each group who had the good or bad outcome, and this calculator will convert to NNT.
Caution in the interpretation of NNT. It should be noted that in practice the interpretation of the NNT should take account of a number of other factors, including how important the consequences of the disease are, the availability of other treatment options, side effects of the treatment and/or its alternatives, costs, patient preferences, etc Any NNT is just a point estimate and as such has some uncertainty around it. By convention, a 95% Confidence Interval (95% CI) is used to indicate the upper and lower limits of the actual NNT so we can say that there is a 95% probability that the true value lies within this range. To look at this another way, if we have an NNT of
Interpretation of OR, RR, HR, and NNT/NNH Analysis Prof. Mary Ferrill summarizes how to interpret an OR, RR, and an HR. First, if the outcome is negative, we want to see that the results of the treatment group should be less than one because that would be considered protective and make fewer patients to experience this bad risk This analysis estimated the number needed to treat with enzalutamide versus bicalutamide to achieve one additional patient with chemotherapy-naïve metastatic castration-resistant prostate cancer who would obtain clinical benefit regarding progression-free survival, radiographic progression-free survival, or no prostate-specific antigen progression at 1 and 2 years following treatment initiation Interpretation of NNT. When asked about interpretation of NNT, 30% of respondents thought that the likelihood of having a treatment effect is one out of the NNT . Thirty-six percent were uncertain about how to interpret the NNT concept Although the calculated NNT value is treatment specific it can be used to compare different drug treatments. In a randomised control trial for Noache, 88 out of 100 still experienced a headache 2 hours after taking the placebo, whereas only 78 out of 100 still experienced a headache in the group taking Noache The concept of patient-years is used in many clinical studies and statistical assessments of risk. Viewing things in these terms allows researchers to look at a population more generally, rather than trying to separate out and process data from each individual member of a group. This concept often.
that the NNT has undesirable statistical properties (1,6). The claim that NNT is easy to understand has little empirical support and has, in fact, been ques-tioned (1,7). Recent evidence from Denmark indicates that neither lay people (8) nor medical doctors (9) readily grasp the concept of NNT. The NNT is the inverse of absolute risk reduction Unfortunately, this is one example where NNTs are incorrectly calculated and presented for the following reasons. 1) Incorrect statistical tests were applied without accounting for the cluster randomization which may lead to spurious positive findings [21]. 2) There are obvious counting errors. For example, the proportions with IOC for girls are given as 18% in the videotape and 14% in the control group, which lead to NNT≈25, not to NNT=10 as reported. 3) No confidence intervals for the estimated NNTs were presented. 4) Proportions and NNTs were rounded much too roughly. 5) Due to the different gender distributions in the groups and the different effect estimates for boys and girls the estimation of an adjusted NNT accounting for gender seems to be preferable to describe the overall average treatment effect. 6) To test whether the treatment effect is significantly different for boys and girls, an appropriate interaction test is required. 7) Only if the interaction test is statistically significant, the conclusion that "Boys in the videotape group showed more improvement … than girls" is valid. In this case, the presentation of different effect estimates for boys and girls is adequate. The best method for data analysis is given by multiple logistic regression with appropriate interaction term and application of the ARD approach. 8) An appropriate explanation of the estimated NNTs is useful but was lacking in the considered example.At a loss really. My daughter is 18 and has suffered with pain in her ankles and wrists for a while. This has now spread and she has ankle, knee and hip pain as well as her wrists.When she wakes she...
The NNT makes it a little more intuitive to see what we are getting for our health care dollars. Conclusion: NNT provides useful context for medical decision-making. The NNT is a legitimate and highly useful way to present medical statistics. It is perhaps more intuitive to understand than relative or absolute risk reduction Understand how to calculate number needed to treat (NNT) as Dr. Seheult tackles this board question provided by BoardVitals. Knowledge of NNT is important for most medical professionals and. The number needed to treat (NNT) is a popular statistic used in medicine and its use is even encouraged by groups like Cochrane and CONSORT.Why is it so popular? Most believe that the NNT is more understandable than effect sizes like odds ratios or risk ratios or statistics like the absolute risk reduction The natural relative effect measure in logistic regression is given by the odds ratio (OR). In the case of no interaction the odds ratio is simply given by exp (b), where b is the estimated regression coefficient. Methods to calculate odds ratios in the case of interactions are described for example by Hosmer and Lemeshow [23]. The OHP effects on dental caries at 5 years in terms of odds ratios in this example are given by OR = 1.20 (95% CI 0.77 to 1.87) for blue collar families and OR = 0.21 (95% CI 0.10 to 0.43) for white collar families demonstrating clearly different relative treatment effects in dependence on occupation. To aid interpretation of the results of a meta-analysis of risk ratios, review authors may compute an absolute risk reduction or NNT. In order to do this, an assumed comparator risk (ACR) (otherwise known as a baseline risk, or risk that the outcome of interest would occur with the comparator intervention) is required
