Neurological adverse events related to lip biopsy in patients suspicious for Sjögren's syndrome: a systematic review and prevalence meta-analysis.

OBJECTIVE: The aim of this study was to compare the prevalence of neurological complications related to lip biopsy for SS diagnosis using conventional vs minimally invasive techniques. METHODS: We performed a systematic review and prevalence meta-analysis using the search strategy [(salivary gland biopsy OR labial biopsy OR lip biopsy) AND (Sjögren)] in the MEDLINE, EMBASE and Web of Science Conference Proceedings Citation Index databases. Studies were selected if they included original data for minor salivary gland biopsy, sample size, exposure of interest (technique description), number of complications and number of affected patients. The prevalence of total and permanent neurological adverse effects was calculated. Both fixed-effects and random-effects pooled estimates were assessed. Heterogeneity was calculated using an adaptation of the DerSimonian and Laird Q test. RESULTS: Sixteen articles were selected for the study. In the minimally invasive group (n = 3), the pooled prevalence of total adverse events is almost four times higher than that in the linear incision group (n = 12) (4.73% vs. 1.20%). In contrast, the pooled prevalence of the permanent or potentially permanent neurological adverse events is 8.5 times lower in the minimally invasive technique group than in the studies using linear incisions (0.17% vs. 1.45%). CONCLUSION: With the limitations intrinsic to the potential biases in the studies included in this meta-analysis, we conclude that the minimally invasive lip biopsy technique for SS diagnosis induces fewer permanent neurological complications than conventional approaches with large linear incisions in the lower lip.

Confidence intervals for heterogeneity measures in meta-analysis.

Two methods of quantifying heterogeneity between studies in meta-analysis were studied. One method quantified the proportion of the total variance of the effect estimate due to variation between studies (RI), and the other calibrated the variance between studies to the size of the effect itself through a between-study coefficient of variation (CVB). Bootstrap and asymptotic confidence intervals for RI and CVB were derived and evaluated in an extensive simulation study that covered a wide range of scenarios likely to be encountered in practice. The best performance was given by asymptotic Wald confidence intervals developed for RI and CVB. The use of these heterogeneity measures together with their confidence intervals was illustrated in 5 typical meta-analyses. A new user-friendly SAS macro (SAS Institute, Inc., Cary, North Carolina) is provided to implement these methods for routine use and can be downloaded at the last author's website.