Prevalence of primary ciliary dyskinesia among patients referred for specialized testing: A systematic review and meta-analysis

Abstract

Background: Signs that raise suspicion for Primary Ciliary Dyskinesia (PCD) include neonatal respiratory distress, chronic wet cough, situs inversus and development of unexplained bronchiectasis. However the prevalence of PCD among suspect patients is unknown. We systematically reviewed the literature and estimated the prevalence of PCD in cohorts of suspect patients referred for diagnostic testing. Methods: All major electronic databases were searched from inception until December 2015 using appropriate terms. Included studies described cohorts of consecutive referrals for PCD testing in which PCD diagnosis was confirmed through a combination of at least two tests. A meta-analysis of proportions using a random effects model was performed and the pooled prevalence of PCD across studies is reported. Results: A total of eight studies were synthesized (referrals: n=2693, PCD: n=727). The pooled prevalence of newly diagnosed PCD patients in cohorts of referrals was 32% (95%CI:25%-39%, I 2 =92.0%) (Fig 1a). Subgroup analysis which excluded studies from the UK led to higher prevalence and also explained most of the heterogeneity in the effect estimate (prevalence:40%, 95%CI:36%-44%, I 2 =19.13%) (Fig 1b). Conclusion: Approximately, only one third of referred patients for PCD testing have eventually PCD confirmed. A revised referral strategy and application of screening tests could improve this figure.