Biostatistics: Calculating Risk Ratios and Number Needed to Treat (NNT)

2013 ◽  
Keyword(s):  
Number Needed To Treat ◽  
Risk Ratios

scholarly journals Systematic review and meta-analysis of gallstone disease treatment outcomes in early cholecystectomy versus conservative management/delayed cholecystectomy

2021 ◽  
Vol 8 (1) ◽  
pp. e000675
Author(s):  
Bhavani Shankara Bagepally ◽  
Madhumitha Haridoss ◽  
Akhil Sasidharan ◽  
Kayala Venkata Jagadeesh ◽  
Nikhil Kumar Oswal
Keyword(s):  
Systematic Review ◽  
Treatment Outcomes ◽  
Conservative Management ◽  
Meta Analysis ◽  
Gallstone Disease ◽  
Biliary Complications ◽  
Number Needed To Treat ◽  
Early Cholecystectomy ◽  
Delayed Cholecystectomy ◽  
Risk Ratios

BackgroundThe effectiveness of early cholecystectomy for gallstone diseases treatment is uncertain compared with conservative management/delayed cholecystectomy.AimsTo synthesise treatment outcomes of early cholecystectomy versus conservative management/delayed cholecystectomy in terms of its safety and effectiveness.DesignWe systematically searched randomised control trials investigating the effectiveness of early cholecystectomy compared with conservative management/delayed cholecystectomy. We pooled the risk ratios with a 95% CI, also estimated adjusted number needed to treat to harm.ResultsOf the 40 included studies for systematic review, 39 studies with 4483 patients are included in meta-analysis. Among the risk ratios of gallstone complications, pain (0.38, 0.20 to 0.74), cholangitis (0.52, 0.28 to 0.97) and total biliary complications (0.33, 0.20 to 0.55) are significantly lower with early cholecystectomy. Adjusted number needed to treat to harm of early cholecystectomy compared with conservative management/delayed cholecystectomy are, for pain 12.5 (8.3 to 33.3), biliary pancreatitis >1000 (50–100), common bile duct stones 100 (33.3 to 100), cholangitis (100 (25–100), total biliary complications 5.9 (4.3 to 9.1) and mortality >1000 (100 to100 000).ConclusionsEarly cholecystectomy may result in fewer biliary complications and a reduction in reported abdominal pain than conservative management.PROSPERO registration number2020 CRD42020192612.

scholarly journals Patient and Physician Preferences for Reporting Research Findings

2019 ◽  
Vol 51 (6) ◽  
pp. 502-508
Author(s):  
Elizabeth Mostofsky ◽  
Jillian A. Dunn ◽  
Sonia Hernández-Díaz ◽  
Murray A. Mittleman
Keyword(s):  
Medical Center ◽  
Treatment Options ◽  
Academic Medical Center ◽  
Cross Sectional Study ◽  
Number Needed To Treat ◽  
Cross Sectional ◽  
Study Staff ◽  
Research Findings ◽  
Additive Measures ◽  
Risk Ratios

Background and Objectives: Although absolute risks provide useful information on the number of excess cases attributable to a harmful exposure or the number of fewer cases attributable to an effective treatment, most research findings are reported in terms of multiplicative effects of exposure on the outcome. We aimed to examine patient and physician preferences for communicating research findings in terms of additive and multiplicative measures of effect and measures of heterogeneity of treatment effects. Methods: We conducted a cross-sectional study of 76 patients and 26 physicians at an academic medical center in Boston, Massachusetts. Trained study staff conducted interviews about interpretations of study findings. Results: Physicians were equally likely to prefer the number needed to harm or the risk ratio as the most useful measure for making informed health decisions, and patients strongly preferred risk ratios. Participants perceived changes in risk as larger when they were presented using multiplicative measures such as risk ratios than when presented as additive measures such as the risk differences or number needed to treat or harm. Conclusions: Despite the importance of considering absolute risks and benefits of treatment options, patients and physicians who rely on study findings for making informed decisions often prefer relative measures.

Rice Fortified with Iron Given Weekly Increases Hemoglobin Levels and Reduces Anemia in Infants: a Community Intervention Trial

2013 ◽  
Vol 83 (1) ◽  
pp. 59-66 ◽  
Author(s):  
Francisco Plácido Nogueira Arcanjo ◽  
Paulo Roberto Santos ◽  
Álvaro Jorge Madeiro Leite ◽  
Francisco Sulivan Bastos Mota ◽  
Sérgio Duarte Segall
Keyword(s):  
Community Intervention ◽  
Capillary Blood ◽  
Number Needed To Treat ◽  
Intervention Trial ◽  
Day Care Centers ◽  
Control Center ◽  
Ferric Pyrophosphate ◽  
Child Day Care ◽  
Child Day Care Centers ◽  
The Impact

More than two billion people suffer from anemia worldwide, and it is estimated that more than 50 % of cases are caused by iron deficiency. In this community intervention trial, we evaluated infants aged 10 to 23 months of age (n = 171) from two public child day-care centers. Intervention lasted 18 weeks. The 50-g individual portion (uncooked) of fortified rice provided 56.4 mg of elemental iron as ferric pyrophosphate. Capillary blood samples to test for anemia were taken at baseline and at endpoint. The objective of this study was to evaluate the impact of rice fortified with iron (Ultrarice®) on hemoglobin and anemia prevalence compared with standard household rice. For the fortified rice center, baseline mean hemoglobin was 113.7 ± 9.2 g/L, and at endpoint 119.5 ± 7.7 g/L, p < 0.0001; for the standard rice center, baseline mean hemoglobin value was 113.5 ± 40.7 g/L, and at endpoint 113.6 ± 21.0, p = 0.99. Anemia prevalence for the fortified rice center was 27.8 % (20/72) at baseline, and 11.1 % (8/72) at endpoint, p = 0.012; for the control center, 47.1 % (33/70) were anemic at baseline, and 37.1 % (26/70) at the end of the study, p = 0.23. The Number Needed to Treat (NNT) was 4. In this intervention, rice fortified with iron given weekly was effective in increasing hemoglobin levels and reducing anemia in infants.

Meta-Analyse zur Wirksamkeit deutscher suchtpräventiver Lebenskompetenzprogramme

2016 ◽  
Vol 25 (3) ◽  
pp. 175-188 ◽  
Author(s):  
Anneke Bühler
Keyword(s):  
Risk Ratios

Zusammenfassung. Schulbasierte Lebenskompetenzprogramme (LKP) sind ein wichtiger Ansatz der Suchtprävention in Deutschland. Ihre Wirksamkeit wurde bisher nicht meta-analytisch getestet. Resultate von 13 systematisch identifizierten randomisierten und nicht-randomisierten Studien mit deutschsprachigen Zielgruppen wurden quantitativ integriert. Risk Ratios (RR) wurden signifikant für den Einstieg in den Tabakkonsum (RR=.77) bzw. das allgemeine Rauchverhalten (RR=.64) bei GrundschülerInnen, bei SekundarstufenschülerInnen ein Initialeffekt von RR=.44 für den aktuellen Konsum. Effekte für die Lebenszeitprävalenz (RR=.78) und den aktuellen Konsum (RR=.71) von Alkohol wurden zum Posttest signifikant. Die Ergebnisse belegen eine Wirksamkeit der suchtpräventiven LKP mit deutsch(sprachig)en SchülerInnen insofern, als dass sie das Risiko für einen frühzeitigen Konsum, der einen Risikofaktor für späteren Substanzmissbrauch darstellt, verringern.

Translocation Relative to Range

Methodology ◽  
2008 ◽  
Vol 4 (3) ◽  
pp. 132-138 ◽  
Author(s):  
Michael Höfler
Keyword(s):  
Risk Difference ◽  
Binary Outcomes ◽  
Number Needed To Treat ◽  
Likert Scales ◽  
Psychological Science ◽  
The Absolute ◽  
The Difference ◽  
Variance Parameters ◽  
Standardized Index ◽  
Maximum Possible Magnitude

A standardized index for effect intensity, the translocation relative to range (TRR), is discussed. TRR is defined as the difference between the expectations of an outcome under two conditions (the absolute increment) divided by the maximum possible amount for that difference. TRR measures the shift caused by a factor relative to the maximum possible magnitude of that shift. For binary outcomes, TRR simply equals the risk difference, also known as the inverse number needed to treat. TRR ranges from –1 to 1 but is – unlike a correlation coefficient – a measure for effect intensity, because it does not rely on variance parameters in a certain population as do effect size measures (e.g., correlations, Cohen’s d). However, the use of TRR is restricted on outcomes with fixed and meaningful endpoints given, for instance, for meaningful psychological questionnaires or Likert scales. The use of TRR vs. Cohen’s d is illustrated with three examples from Psychological Science 2006 (issues 5 through 8). It is argued that, whenever TRR applies, it should complement Cohen’s d to avoid the problems related to the latter. In any case, the absolute increment should complement d.

Kritik beim Einsatz der medikamentösen Osteoporose-Therapie

2019 ◽  
Vol 28 (02) ◽  
pp. 131-135
Author(s):  
Peter Burckhardt
Keyword(s):  
Vitamin D ◽  
Number Needed To Treat

ZusammenfassungStudien über neue Medikamente für Osteoporose berichteten über die Verhütung von radiologischen Wirbelkörper (WK)-Frakturen, aber meist mit einer zu freien Definition dieser Frakturen. Radiologische Frakturen sind häufiger als die klinischen WK-Frakturen, was die Studien erleichtert, aber sie sind zu einem Drittel asymptomatisch. Die Resultate solcher Studien wurden auch oft verschönert mit der Angabe der relativen Fraktur-Verminderung, und nicht mit der wirklichen Verminderung der Frakturinzidenz. Damit konnte eine wirkliche Frakturinzidenz-Verminderung von nur 1 % als 50 % angegeben werden. Was Hüftfrakturen angeht, ist der NNT (Number Needed to Treat), die Anzahl von Patienten, die behandelt werden müssen um eine Fraktur zu verhüten, sehr oft so hoch, dass ein günstiges Kosten/Nutzen-Verhältnis fraglich wird. Meistens ist er wahrscheinlich auch zu hoch für WK-Frakturen bei Patienten ohne vorgängige WK-Fraktur. Die Erwähnung des NNT wird nicht nur von der Pharma-Industrie vermieden, sondern auch von den meisten Autoren. Weiterhin wird oft nicht das beste und preisgünstigste Medikament verschrieben (orale versus parenterale Bisphosphonate, Calcium mit Vitamin D versus Vitamin D und Calciumreiche Nahrung). Es ist auch bedauerlich, dass Fluor von der Pharma-Industrie nicht unterstützt wurde, und dass das Medikament wegen der toxischen Dosen verurteilt wurde. Die positiven Studien mit kleinen, hoch wirksamen Dosen wurden außer Acht gelassen.

Is it Worth CANVASing for CREDENCE? A Benefit-risk Analysis

2020 ◽  
Vol 16 (5) ◽  
pp. 509-514
Author(s):  
Binayak Sinha ◽  
Samit Ghosal
Keyword(s):  
Adverse Events ◽  
Fungal Infections ◽  
Absolute Risk ◽  
Pooled Analysis ◽  
Major Adverse Cardiovascular Events ◽  
Number Needed To Treat ◽  
Pooled Data ◽  
The Individual ◽  
Fracture Risks ◽  
Number Needed To Harm

Background and Aims: A number of significant positive and negative signals emerged from the CANVAS Program and CREDENCE trial with the use of canagliflozin. These signals are confusing. A Likelihood of being Helped of Harmed (LHH) analysis was conducted to determine the risk, benefit ratio associated with canagliflozin use and address the signals as a continuum. Materials &Methods: LHH was calculated from the number needed to treat (NNT) and number needed to harm (NNH) available from the absolute risk reductions reported with the outcomes of interest, in these two trials. Results: In the CANVAS Program, LHH for major adverse cardiovascular events (MACE) points at a significant benefit with canagliflozin use in comparison to amputation (1.65), fractures (1.65) and euglycaemic diabetic ketoacidosis (euDKA) (16.67) risks. Only genital fungal infections were significant more in both sexes (0.21-M and 0.1-F) when LHH was matched against the positive outcomes. In contrast, the hHF benefits were outweighed by amputation (0.95) and fracture risks (0.95). : In CREDENCE trial, the LHH for Primary composite, Renal composite and MACE, all supported the benefits in comparison to any adverse events encountered in the trial. : The LHH from pooled data (CANVAS Program and CREDENCE trial) was in favour of all the benefits (hHF and renal composites) except for MACE matched against amputation (0.66). Conclusion: The outcome benefits were in favour of canagliflozin in comparison to all reported adverse events, when hHF and renal composite were under consideration, in both the individual and pooled LHH analysis. However, the MACE benefits were overwhelmed by amputation risk in the pooled analysis.

Sign in / Sign up

Export Citation Format

Share Document