Age Distribution, Comorbidities and Risk Factors for Thrombosis in Prader-Willi Syndrome

Abstract

: Prader-Willi syndrome (PWS) is an imprinting disorder caused by lack of expression of the paternally inherited 15q11.2-q13 chromosome region. The risk of death from obesity-related complications can worsen with age, but survival trends are improving. Comorbidities and their complications such as thrombosis or blood clots and venous thromboembolism (VTE) are uncommon but reported in PWS. Two phases of analyses were conducted in our study: unadjusted and adjusted frequency with odds ratios and a regression analysis of risk factors. Individuals with PWS or non-PWS controls with exogenous obesity were identified by specific International Classification of Diseases (ICD)-9 diagnostic codes reported on more than one occasion to confirm the diagnosis of PWS or exogenous obesity in available national health claims insurance datasets. The overall average age or average age per age interval (0-17yr, 18-64yr, and 65yr+) and gender distribution in each population were similar in 3136 patients with PWS and 3945 non-PWS controls for comparison purposes, with exogenous obesity identified from two insurance health claims dataset sources (i.e., commercial and Medicare advantage or Medicaid). For example, 65.1% of the 3136 patients with PWS were less than 18 years old (subadults), 33.2% were 18-64 years old (adults), and 1.7% were 65 years or older. After adjusting for comorbidities that were identified with diagnostic codes, we found that commercially insured PWS individuals across all age cohorts were 2.55 times more likely to experience pulmonary embolism (PE) or deep vein thrombosis (DVT) than for obese controls (p-value: 0.013; confidence interval (CI) :1.22-5.32). Medi caid-insured individuals across all age cohorts with PWS were 0.85 times more likely to experience PE or DVT than obese controls (p-value: 0.60; CI: 0.46-1.56), with no indicated age difference. Age and gender were statistically significant predictors of VTEs, and they were independent of insurance coverage. There was an increase in occurrence of thrombotic events across all age cohorts within the PWS patient population when compared with their obese counterparts, regardless of insurance type.

Keywords: Prader–Willi syndrome; confirmatory ICD-9 diagnostic codes; deep venous thrombosis; individuals with exogenous obesity; insurance health claims; pulmonary embolism; thrombosis.

Figure 1

Iterative statistical stepwise approach to determine the risk factors that contributed significantly to thrombosis events.

Figure 2

Age distribution bar graph of patients with Prader–Willi syndrome (PWS) and non-PWS obese controls.

Figure 3

Adjusted primary thrombosis events of patients with Prader–Willi syndrome (PWS) in comparison to non-PWS obese patients across all age cohorts, insurances, and analyses.

Figure 4

Primary thrombosis events in patients with Prader–Willi syndrome and non-PWS obese controls on commercial/Medicare coverage across all age cohorts with confirmatory codes in Analysis 2 (A), Analysis 4 (B) and Analysis 5 (C).