The Potential of a Stroke Registry Using Diagnosis Procedure Combination Data from All Hospitals in a Japanese Prefecture.

Objectives: In Japan, many hospitals have joined the diagnosis procedure combination/per-diem payment system (DPC/PDPS), which provides unified information about inpatients. DPC data are digitized, and the number of participating hospitals has increased recently. Herein, we evaluated the potential of a stroke registry constructed using these unified DPC data from all hospitals in the Iwate Prefecture, Japan.

Methods: The proportion of cerebrovascular disease (CVD) cases registered by DPC-participating hospitals was calculated and compared with all registered cases in the Iwate Stroke Registry in 2008-2017. The cases were categorized based on sex, age-groups, stroke subtypes, and first-ever onset or recurrence onset. Based on the registered cases in the stroke registry, the accuracy of the CVD cases extracted by the disease name from DPC data of a typical core hospital and a typical noncore hospital was evaluated.

Results: Of the 71 hospitals with 9,992 beds in the Iwate Prefecture in 2018, 50 hospitals with 8,316 beds participated in the DPC system. The proportion of registered cases from participating hospitals was 95.2% (44,779/47,018) for all stroke types (95.6% men and 94.9% women), 94.3% for cerebral infarction, 97.0% for intracerebral hemorrhage, and 98.7% for subarachnoid hemorrhage, whereas it was 95.7% for first-ever onset and 94.1% for recurrent onset. The proportion of registered cases decreased with increasing patient age. Attending doctors and researchers registered 486 and 41 CVD cases from the core and noncore hospitals, respectively, whereas 455 and 46 CVD cases were extracted from the DPC data of these hospitals, respectively. This yielded 86.6% sensitivity, 99.3% specificity, 92.5% positive predictive value, and 98.7% negative predictive value for the core hospital; these values were 92.7%, 98.6%, 82.6%, and 99.5%, respectively, for the noncore hospital.

Discussion/conclusions: The stroke registry constructed using DPC data from all hospitals of Iwate Prefecture appears to be adequately complete and accurate.