A Retrospective, Longitudinal, Claims-Based Comparison of Concomitant Diagnoses Between Individuals with and Without Down Syndrome.

Background: Individuals with Down syndrome (DS) experience various comorbidities in excess of the prevalence seen among the non-DS population. However, the extent of the excess burden of comorbidities specifically within commercially and publicly insured DS populations aged < 21 years is not currently known.

Objectives: To (a) describe the most common diagnoses among individuals with DS who have either commercial or Medicaid insurance and (b) compare the prevalence of those diagnoses between DS cases and non-DS controls.

Methods: This was a longitudinal, retrospective study using health care claims of commercially insured and Medicaid-insured individuals in the Truven Health MarketScan Databases from 2008 to 2015. Individuals aged < 2, 2-5, 6-11, and 12-20 years with a DS diagnosis (cases; commercial: n = 15,948; Medicaid: n = 11,958) were matched to individuals without DS (controls; commercial: n = 47,844; Medicaid: n = 35,874) using a 1:3 ratio. The annual number of diagnoses was compared between cases and controls within age groups using t-tests, and the prevalence of the most common diagnoses was compared using chi-square tests.

Results: Cases in all age groups in both databases had more diagnoses annually than controls (mean =9-17 per year vs. 4-10 per year, P < 0.001), and the number of diagnoses decreased with age for cases and controls. Among the most common case diagnoses were upper respiratory infections (28.9%-59.1% vs. 19.5%-52.9%); suppurative otitis media (25.1%-56.8% vs. 8.7%-51.2%); nutrition/metabolic/developmental symptoms (37.9%-50.4% vs. 7.7%-10.6%); delays in development (22.8%-52.8% vs. 4.1%-10.9%); and general symptoms (35.1%-47.2% vs. 22.1%-37.2%), and the prevalence of each was greater among cases versus controls in all age groups in both databases (P < 0.001). The most common diagnoses among controls included some of the same as among cases, as well as acute pharyngitis (18.7%-31.8% vs. 19.2%-30.5%); allergic rhinitis (19.9%-24.3% vs. 15.3%-20.7%); viral/chlamydial infections (24.2%-26.6% vs. 17.7%-23.5%); and joint disorders (11.6% vs. 16.6%), and most were significantly more prevalent among cases (P < 0.05).

Conclusions: Commercially insured and Medicaid-insured individuals aged < 21 years with DS experience a greater number and prevalence of concomitant diagnoses compared with non-DS individuals. Awareness of these common diagnoses could help facilitate the optimal care of these individuals by the pediatric health care community.

Disclosures: This study was sponsored and funded by Genentech. Truven Health Analytics, an IBM Company, receives payment from Genentech to conduct research, including the research for this study. Truven Health Analytics also receives payment from other pharmaceutical companies to conduct research. Kong and Evans are employed by Truven Health Analytics. Csoboth is employed by Genentech. Brixner reports fees paid to the University of Utah by Truven Health Analytics on her behalf for work related to this study. Hurley reports fees from Genentech for work on this study and for work outside of this study. At the time of this study, Visootsak was employed by F. Hoffman-LaRoche Pharmaceuticals, parent company of Genentech. All authors, including those affiliated with the study sponsor, were involved in the design of the study, interpretation of the data, writing of the manuscript, and the decision to submit the manuscript for publication. Study concept and design were contributed by Kong, Hurley, and Brixner, along with Evans. Kong and Evans collected the data, and data interpretation was performed by Csoboth, Visootsak, Brixner, and Hurley, with assistance from Kong. The manuscript was written by Evans, Kong, Hurley, and Brixner and revised by Kong, Hurley, Evans, and Brixner, with assistance from Csoboth and Visootsak.