Multiple imputation procedures allow the rescue of missing data: an application to determine serum tumor necrosis factor (TNF) concentration values during the treatment of rheumatoid arthritis patients with anti-TNF therapy.
Longitudinal studies aimed at evaluating patients clinical response to specific therapeutic treatments are frequently summarized in incomplete datasets due to missing data. Multivariate statistical procedures use only complete cases, deleting any case with missing data. MI and MIANALYZE procedures of the SAS software perform multiple imputations based on the Markov Chain Monte Carlo method to replace each missing value with a plausible value and to evaluate the efficiency of such missing data treatment. The objective of this work was to compare the evaluation of differences in the increase of serum TNF concentrations depending on the -308 TNF promoter genotype of rheumatoid arthritis (RA) patients receiving anti-TNF therapy with and without multiple imputations of missing data based on mixed models for repeated measures. Our results indicate that the relative efficiency of our multiple imputation model is greater than 98% and that the related inference was significant (p-value < 0.001). We established that under both approaches serum TNF levels in RA patients bearing the G/A -308 TNF promoter genotype displayed a significantly (p-value < 0.0001) increased ability to produce TNF over time than the G/G patient group, as they received successively doses of anti-TNF therapy.
School of Public Health, Faculty of Medicine, University of Chile, Santiago, Casilla.
Irene
I
Schiattino
Rodrigo
R
Villegas
Andrea
A
Cruzat
Jimena
J
Cuenca
Lorena
L
Salazar
Octavio
O
Aravena
Bárbara
B
Pesce
Diego
D
Catalán
Carolina
C
Llanos
Miguel
M
Cuchacovich
Juan C
JC
Aguillón
D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000188:drug therapy* / Q000235:genetics; D005838:Genotype; D006801:Humans; D000069285:Infliximab; D015233:Models, Statistical; D009010:Monte Carlo Method; D015999:Multivariate Analysis; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis* / Q000037:antagonists & inhibitors / Q000235:genetics
D000911:Antibodies, Monoclonal; D018501:Antirheumatic Agents; D014409:Tumor Necrosis Factor-alpha; D000069285:Infliximab