Phenotypes and body mass in women with polycystic ovary syndrome identified in referral versus unselected populations: systematic review and meta-analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational studies
PubMed 27530062 · doi:10.1016/j.fertnstert.2016.07.1121
What was done
A systematic review and meta-analysis of observational studies from PubMed, EMBASE, and the Cochrane Library (2003–2016) was conducted to compare polycystic ovary syndrome (PCOS) phenotypes and body mass index (BMI) between referral and unselected cohorts. The analysis included 41 studies reporting on 43 populations (13,796 reproductive-age women diagnosed by Rotterdam 2003 criteria). Pooled prevalence estimates were calculated for phenotypes A (hyperandrogenism [HA] + oligo-/anovulation [OA] + polycystic ovarian morphology [PCOM]), B (HA + OA), C (HA + PCOM), and D (OA + PCOM).
What was found
Prevalence estimates differed significantly between referral and unselected populations for phenotypes A, B, and C: - Phenotype A: 50% (95% CI, 46%–54%) referral vs. 19% (95% CI, 13%–27%) unselected. - Phenotype B: 13% (95% CI, 11%–17%) referral vs. 25% (95% CI, 15%–37%) unselected. - Phenotype C: 14% (95% CI, 12%–16%) referral vs. 34% (95% CI, 25%–46%) unselected. - Phenotype D: 17% (95% CI, 13%–22%) referral vs. 19% (95% CI, 14%–25%) unselected (not statistically significant). Referral PCOS patients had a significantly higher mean BMI than local controls, a pattern not found in unselected PCOS cohorts.
Why it matters
This demonstrates marked referral bias in clinical PCOS research, indicating that clinic-based studies disproportionately represent more severe, complete phenotypes and higher BMI compared to community-based populations.
Limits
The analysis relied exclusively on observational studies, introducing potential variability in diagnostic definitions and baseline characteristics. The abstract does not provide exact numerical values for BMI differences or measures of study heterogeneity.
Cited by
- supports PCOS has four distinct phenotypes.