Objective  To explore comorbidity pattern, comorbidity burden and economic burden of chronic diseases among inpatients with Parkinson's disease and Parkinsonism in Chengdu city, Sichuan province for effective treatment and management of the patients with the diseases.

  Methods  Based on disease codes of International Classification of Diseases 10th Revision, we collected 30 436 hospitalization records of Parkinson's disease patients and 3 749 records of Parkinsonism patients for years of 2013 – 2017 from the Information System of Chengdu Medical Insurance Bureau. The comorbidity burden of chronic diseases among the inpatients was evaluated with Charlson Comorbidity Index (CCI). The comorbidity spectrum, comorbidity burden and economic burden of chronic disease among the inpatients with Parkinson's disease and Parkinsonism were described and compared statistically; the influence of CCI on economic burden of the inpatients was analyzed with multivarite linear regression model.

  Results  The ratios of chronic disease comorbidity were 72.23% and 73.26% for 30 436 hospitalizations of Parkinson′s disease patients and 3 740 hospitalizations of inpatients with Parkinsonism during the 5-year period in Chengdu city and there was no significant difference in the ratio between the two groups of hospitalization (χ² = 1.78, P = 0.182). For hospitalizations of both Parkinson′s disease and Parkinsonism patients, the top three most frequent comorbidity diseases (constituent ratios) were cerebrovascular disease (49.21% and 51.23%), chronic pulmonary disease (19.25% and 20.64%) and diabetes with end-organ damage (15.54% and 16.34%). In terms of multicomorbidity, the most frequent comorbid pattern of two chronic diseases was cerebrovascular disease and chronic pulmonary disease (9.45% and 11.34% for both Parkinson′s disease and Parkinsonism hospitalizations) and that of three chronic diseases was cerebrovascular disease, chronic pulmonary disease, and diabetes with end-organ damage (1.30% and 2.03%); for the 21 983 hospitalizations of Parkinson's disease patients and 2 740 hospitalizations of Parkinsonism patients, the proportions of with 1, 2, 3, 4, and ≥ 5 comorbid chronic diseases were 51.95% and 47.34%, 34.67% and 35.51%, 11.44% and 14.01%, 1.74% and 2.99%, and 0.20% and 0.15%, respectively, with a significant difference in the proportions between the two groups of hospitalization (χ² = 45.21, P < 0.001). For the hospitalizations of Parkinson′s disease and Parkinsonism patients, the average CCI of 1.39 ± 1.28 and 1.49 ± 1.36 and the average medical expenses per hospitalization were 11 031.75 ± 110.88 and 12 885.81 ± 288.57 (Chinese yuan), with significant differences in the CCI and the average medical expenses between the hospitalizations of the two groups of the inpatients (both P < 0.001). After adjusting for gender, age, hospital grade and length of stay, the results of multivariate linear regression analysis showed no significant difference in the average medical expenses per hospitalization between the hospitalizations of Parkinson′s disease and Parkinsonism patients (β = 0.017, 95% confidence interval 95%CI: – 0.003 – 0.071); while, the expenses increased with the increment of CCI (β = 0.066, 95%CI: 0.061 – 0.071).

  Conclusion  The prevalence, disease and the economic burden of comorbidity of chronic diseases were high and cerebrovascular disease, chronic pulmonary disease, and diabetes with end-organ damage were the most common comorbidities among inpatients of Parkinson's disease and Parkinsonism in Chengdu city.