METHODOLOGICAL AND STATISTICAL PROBLEMS IN SLEEP-APNEA RESEARCH - THELITERATURE ON UVULOPALATOPHARYNGOPLASTY

A comprehensive review of the literature on the surgical treatment of sleep apnea found 37 appropriate papers (total n = 992) on uvulopalato pharyngoplasty (UPPP). Methodological and statistical problems in thes e papers included the following: 1) There were no randomized studies a nd few (n = 4) with control groups. 2) Median sample size was only 21. 5; thus statistical power was low and clinically important association s were routinely classified as ''not statistically significant''. 3) O nly one paper presented the confidence bounds that might distinguish b etween statistical and clinical significance. 4) Because of short foll ow-up time and infrequent repeat follow-ups, little is known about whe ther UPPP results deteriorate with time. 5) In at least 15 papers, bia s caused by retrospective designs and nonrandom loss to follow-up rais ed questions about the generalizability of results. 6) Few papers asso ciated polysomnographic data with patient-based quality of life measur es. 7) Missing data and missing and inconsistent definitions were comm on. 8) Baseline measures were often biased because the same assessment was inappropriately but routinely used for both screening and baselin e. We conclude that because of these and other problems, there is much that is needlessly unknown about UPPP. It is the responsibility of th e research and professional communities to define training, editorial and review procedures that will raise the methodological and statistic al quality of published research.