Handling missing quality of life data in HIV clinical trials: what is practical?
Handling missing quality of life data in HIV clinical trials: what is practical?
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DOI:
10.1007/s11136-007-9284-3
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发表时间:
2008-02-01
影响因子:
3.5
通讯作者:
Wu, Albert W.
中科院分区:
文献类型:
--
作者:
Fairclough, Diane L.;Thijs, Herbert;Wu, Albert W.
Aims Missing health-related quality of life ( HRQOL) data in clinical trials can impact conclusions but the effect has not been thoroughly studied in HIV clinical trials. Despite repeated recommendations to avoid complete case ( CC) analysis and last observation carried forward ( LOCF), these approaches are commonly used to handle missing data. The goal of this investigation is to describe the use of different analytic methods under assumptions of missing completely at random ( MCAR), missing at random ( MAR), and missing not at random ( MNAR) using HIV as an empirical example.Methods Medical Outcomes Study HIV ( MOS-HIV) Health Survey data were combined from two large open-label multinational HIV clinical trials comparing treatments A and B over 48 weeks. Inclusion in the HRQOL analysis required completion of the MOS-HIV at baseline and at least one follow-up visit ( weeks 8, 16, 24, 40, 48). Primary outcomes for the analysis were change from week 0 to 48 in mental health summary ( MHS), physical health summary ( PHS), pain and health distress scores analyzed using CC, LOCF, generalized estimating equations ( GEE), direct likelihood and sensitivity analyses using joint mixed-effects model, and Markov chain Monte Carlo ( MCMC) multiple imputation. Time and treatment were included in all models. Baseline and longitudinal variables ( adverse event and reason for discontinuation) were only used in the imputation model.Results A total of 511 patients randomized to treatment A and 473 to treatment B completed the MOS-HIV at baseline and at least one follow-up visit. At week 48, 71% of patients on treatment A and 31% on treatment B completed the MOS-HIV survey. Examining changes within each treatment group, CC and MCMC generally produced the largest or most positive changes. The joint model was most conservative; direct likelihood and GEE produced intermediate results; LOCF showed no consistent trend. There was greater spread for within-group changes than between-group differences ( within MHS scores for treatment A: 0.1 to 1.6, treatment B: 0.4 to 2.0; between groups: -0.7 to 0.4; within PHS scores for treatment A: -1.5 to 0.4, treatment B: -1.7 to -0.2; between groups: 0.1 to 1.1). The size of within-group changes and between group differences was of similar magnitude for the pain and health distress scores. In all cases, the range of estimates was small