The respiratory disease burden of non-traumatic fractures for adults with cerebral palsy

Background: Individuals with cerebral palsy (CP) are vulnerable to non-trauma fracture (NTFx) and premature mortality due to respiratory disease (RD); however, very little is known about the contribution of NTFx to RD risk among adults with CP. The purpose of this study was to determine if NTFx is a risk factor for incident RD and if NTFx exacerbates RD risk in the adult CP population. Methods: Data from 2011 to 2016 Optum Clinformatics(R) Data Mart and a random 20% sample Medicare fee-for-service were used for this retrospective cohort study. Diagnosis codes were used to identify adults (18+ years) with and without CP, NTFx, incident RD at 3-, 6-, 12-, and 24-month time points (pneumonia, chronic obstructive pulmonary disease, interstitial/pleura disease), and comorbidities. Crude incidence rates per 100 person years of RD were estimated. Cox regression estimated hazard ratios (HR and 95% confidence interval [CI]) for RD measures, comparing: (1) CP and NTFx (CP + NTFx); (2) CP without NTFx (CP w/o NTFx); (3) without CP and with NTFx (w/o CP + NTFx); and (4) without CP and without NTFx (w/o CP w/o NTFx) after adjusting for demographics and comorbidities. Results: The crude incidence rate was elevated for CP + NTFx vs. CP w/o NTFx and w/o CP + NTFx for each RD measure. After adjustments, the HR was elevated for CP + NTFx vs. CP w/o NTFx for pneumonia and interstitial/pleura disease at all time points (all P < 0.05), but not chronic obstructive pulmonary disease (e.g., 24-month HR = 1.07; 95%CI = 0.88-1.31). The adjusted HR was elevated for CP + NTFx vs. w/o CP + NTFx for pneumonia at all time points, interstitial/pleura disease at 12- and 24-month time points, and chronic obstructive pulmonary disease at 24-months (all P < 0.05). There is evidence of a time-dependent effect of NTFx on pneumonia and interstitial/pleura disease for CP + NTFx as compared to CP w/o NTFx. Conclusions: Study findings suggest that NTFx is a risk factor for incident RD, including pneumonia and interstitial/pleura disease, among adults with CP and that NTFx exacerbates RD risk for adults with vs. without CP.