A pseudo-random patient sampling method evaluated.
Oct 19 2016
OBJECTIVE:To compare two HIV cohorts to determine whether a pseudo-random sample can represent the entire study population.
STUDY DESIGN AND SETTING:HIV-positive patients receiving care at 8 sites in 7 Asian countries. TAHOD pseudo-randomly selected a patient sample, while TAHOD-LITE included all patients. We compared patient demographics, CD4 count and HIV viral load testing for each cohort. Risk factors associated with CD4 count response, HIV viral load suppression (<400 copies/mL) and survival were determined for each cohort.
RESULTS:There were 2318 TAHOD patients and 14714 TAHOD-LITE patients. Patient demographics, CD4 count and HIV viral load testing rates were broadly similar between the cohorts. CD4 count response and all-cause mortality were consistent among the cohorts with similar risk factors. HIV viral load response appeared to be superior in TAHOD and many risk factors differed, possibly due to viral load being tested on a subset of patients.
CONCLUSIONS:Our study gives the first empirical evidence that analysis of risk factors for completely ascertained endpoints from our pseudo-randomly selected patient sample may be generalized to our larger, complete population of HIV-positive patients. However, results can significantly vary when analysing smaller or pseudo-random samples, particularly if some patient data are not completely missing at random, such as viral load results.