scholarly journals Planning clinically relevant biomarker validation studies using the “number needed to treat” concept

2016 ◽  
Vol 14 (1) ◽  
Author(s):  
Roger S. Day
Keyword(s):  
Validation Studies ◽  
Number Needed To Treat ◽  
Biomarker Validation

scholarly journals Statistical inference for net benefit measures in biomarker validation studies

Biometrics ◽  
2019 ◽  
Vol 76 (3) ◽  
pp. 843-852
Author(s):  
Tracey L. Marsh ◽  
Holly Janes ◽  
Margaret S. Pepe
Keyword(s):  
Statistical Inference ◽  
Validation Studies ◽  
Net Benefit ◽  
Biomarker Validation

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.

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.

Stress and symptoms of stress with biomarker validation

2013 ◽  
Author(s):  
Michael Hack ◽  
Calli Deruby ◽  
Scott Cohn
Keyword(s):  
Biomarker Validation

Salt-fog artificial-pollution validation studies

1970 ◽  
Vol 117 (7) ◽  
pp. 1389
Author(s):  
H.M. Ryan ◽  
J.M. Mattingley
Keyword(s):  
Validation Studies ◽  
Salt Fog

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.

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