Objective : To elucidate the availability and applicability of the information contained in health insurance claims to pharmacoepidemiological studies with particular reference to the computerization of insurance claims submitted by dispensing pharmacies.
Data Sources : Outpatient insurance claims of two health insurance societies based in the Kanto region. The survey, funded by the Federation of Health Insurance Societies, was undertaken as part of a demonstration project to develop methodologies for insurers to evaluate the clinical performance of providers.
Study Selection : Disease-specific, provider-specific and clinical procedure specific comparison of the per-claim cost. All claims from pharmacies were matched with the prescribing hospitals or clinics to capture the entire medication.
Data Extraction : All claims were reviewed by trained reviewers and procedure specific costs were classified into five disease categories to obtain the best estimate of disease-specific cost.
Results : Inter-provider variations were assessed based on overlapping of the overall average and the confidence interval of the doubled standard error after adjusting for age. Contrary to popular belief, academic medical centers showed significantly lower medication cost than clinics for the treatment of acute upper respiratory infection. Prescription pattern to favor high cost antibiotics accounted for higher per-claim medication cost of clinics with concentration of high cost claims.
Conclusion : Based on the authors' experience and methodologies developed, computerization of insurance claims will achieve consistency, efficiency and timelines which are of utmost importance for pharmacoepidemiological studies. On the other hand, insurers may preempt the claims review and reimbursement organizations by appealing to the pharmacy claims through electronically matching the prescribing claims. The nature of evidence sought by both pharmacoepidemiological researchers and insurers, whether it be for the purpose of post-marketing survey or cost cutting, would eventually converge.

During the eleven years from January 1978 to December 1988, we experienced 1, 287 cases of gastric cancer, hospitalized in the surgical department of Tsuchiura Kyodo Hospital which is located in the southern agricultural district of Ibaraki Prefecture.
Among these 1, 287 cases, 1, 233 patients were operated on. Gastric resection was performed in 1, 059 cases including 337 cases of total gastrectomy with the resection rate of 85.9 percent (1, 059/1, 233). In 863 cases, resection gave histologically satisfactory results, and our curative resection rate was 70.0 percent (863/1, 233). Direct mortality rate was 2.35% in all operated cases and 1.32% in resected cases.
The five-year survival rate over the period from 1978 to 1983 was 57.7% in all resected cases and 69.3% in curatively resected cases.
Annual follow up observation showed increases in resection rate, curative resection rate, and five-year survival rate. However, there were no remarkable changes in the rate of total gastrectomy, rate of combined resection of other organs, and degree of lymph nodes dissection.
The main factor contributing to the improvement in the results of surgical treatment of gastric cancer was the increase in the detection rate of cancer in relatively early stages, through gastric mass survey or total check-up in the asymptomatic stage.