OBJECTIVES: This study assesses disease burden and treatment costs in patients with Paget’s Disease (PD) compared with a matched comparator group (MC). METHODS: This is an observational study using 2001-2002 MarketScan Research databases (MEDSTAT, Ann Arbor, MI), which consist of medical claims, prescriptions and encounter data on 2 million active and retired USA employees. Details include age, gender, drugs prescribed, medical services rendered, ICD-9 diagnostic codes and costs. We linked annual files to create a longitudinal panel with 24 months of observation. Persons with PD were identified by ICD-9 code 731.0. A MC was selected using gender, age and risk adjustment score, which was derived from a DCG/HCC classification system based on presence of 189 medical conditions. In this analysis, we calculated the prevalence of 30 conditions linked to PD and total costs for all medical care. The prevalence of co-morbidities and health care costs were compared in PD and MC, and differences tested using chi-square and t-tests, as appropriate. RESULTS: Our study identified 488 individuals, 244 with PD and 244 matched comparators (MC). The average age was 72.7 years; 50.8% were female. Largest differences in co-morbidities detected between PD patients and MC were: pathological fractures (4.9% vs. 0.4%), heart murmurs (3.3% vs. 0.4%), fractures of femur other than neck (2.9% vs. 0.4), spinal stenosis (2.5% vs. 0.4%), hypercalcemia (1.6% vs. 0.4%), and bone neoplasms (7.8% vs. 2.5%), respectively. Annual per patient outpatient costs were significantly higher in PD patients (PD $10,687 vs. MC $8,083 (p <0.05)), especially associated with compression fractures, heart murmurs, and spinal stenosis. Inpatient costs (PD $7045 vs. MC $7514), and prescription costs (PD $5312 vs. MC $4844) were comparable. CONCLUSIONS: This study is the first to link higher treatment costs with increased prevalence of co-morbidities associated with PD.