Comparison of the French DRG based information system (PMSI) with the National Mesothelioma Surveillance Program database

Background: One of the main purposes of the French National Mesothelioma Surveillance Program is to estimate and follow the national incidence of pleural mesothelioma. We wanted to study the contribution of the French hospital national database as a valid source of mesothelioma incident cases. Methods: From the 1998 and 1999 hospital national database, medical records with a diagnosis code of mesothelioma or pleural cancer where selected among patients who resided in one of the 17 administrative divisions covered by the National Mesothelioma Surveillance Program in 1998. From these records, 506 patients in 1998 and 474 patients in 1999 where identified and matched with the National Mesothelioma Surveillance Program cases over the same period using indirect criteria of identification (sex, age, place of residence). Medical records of cases unknown by the National Mesothelioma Surveillance Program where consulted in one of the administrative divisions. Results: Only two-thirds of the registered cases of the National Mesothelioma Surveillance Program could be matched with a patient identified in the hospital national database with a diagnosis of mesothelioma registered during the same year. Consultation of the medical records showed that 1) certified cases registered in the National Mesothelioma Surveillance Program where often (83%)found in the hospital national database with a code of mesothelioma but 10 to 15% of the patients with a code of mesothelioma in the national hospital databases had a different diagnosis according to their medical records; 2) 65% of the patients with a code of mesothelioma in the national hospital databases that where unknown from the National Mesothelioma Surveillance Program in 1998 and 55% in 1999 where prevalent cases; 3) 3 suspected cases had not been reported to the National Mesothelioma Surveillance Program. Conclusion: Because of lack of diagnosis certification, mistakes in encoding diagnosis and the fact that incident and prevalent cases cannot be distinguished in the hospital national database make it impossible to estimate the mesothelioma incidence solely from this source of data. However, the hospital claim databases constitute a complementary source of information for the active search of incident cases performed by the National Mesothelioma Surveillance Program.