Incidence of lymphedema among adults with cerebral palsy.

Background: Lymphedema is a chronic and progressive condition but is understudied among adults with cerebral palsy (CP).

Objective: To compare the 2-year incidence of lymphedema between adults with versus without CP before and after accounting for multimorbidity, cancer diagnosis/treatment, and lymph node/channel surgery.

Design: Retrospective cohort study.

Setting: Nationwide commercial claims data from January 1, 2011 to December 31, 2017.

Participants: Adults ≥18 years old with and without CP with at least 12 months of continuous health plan enrollment, defined as the baseline period, were included for analysis. The 12-month baseline period was used to establish information on preexisting lymphedema (for exclusion), presence of cancer, including radiation treatment and lymph node surgery, and the Whitney Comorbidity Index (WCI).

Interventions: Not applicable.

Main outcome measure: The 2-year incidence rate (IR) and IR ratio (IRR) of lymphedema were evaluated. Cox regression estimated the hazard ratio (HR) of 2-year lymphedema after adjusting for age, gender, WCI, cancer diagnosis/treatment, and lymph node/channel surgery.

Results: The 2-year IR of lymphedema was 5.73 (95% confidence interval [CI] = 4.59-6.88) for adults with CP (n = 9922) and 1.81 (95% CI = 1.79-1.83) for adults without CP (n = 12,932,288); the IRR was 3.17 (95% CI = 2.59-3.87) and the adjusted HR was 2.43 (95% CI = 1.98-2.98). There was evidence of effect modification by gender, age, and WCI score. All HRs were elevated, but men with versus without CP had higher HRs than women with versus without CP; HRs for adults with versus without CP were higher for younger participants and those with lower WCI scores.

Conclusions: Adults with CP had a higher 2-year rate of lymphedema compared with those without CP. Men with CP had a disproportionately higher rate than women with CP when compared with their gender-based reference cohorts without CP.