Which ICD‐9 codes were assigned for malignant mesothelioma in the mortality data in the United States before the ICD‐10 was introduced?

Abstract

Background: Malignant mesothelioma (MM) is rare and fatal; survival in most cases is only about one year. Mortality rate is, therefore, a good proxy measure of incidence rate. However, the specific International Classification of Diseases (ICD) code for MM was not available until the Tenth Revision ICD (ICD-10). Little is known on which Ninth Revision ICD (ICD-9) codes were assigned for MM in the ICD-9 era. Methods:We used a 1996 double-coded mortality file compiled by the National Center for Health Statistics to calculate the detection rate (DR) and confirmation rate (CR) of selected ICD-9 codes.Results: Of 2386 decedents whose underlying cause of death was MM (ICD-10 code C45), the DR (deaths) of corresponding ICD-9 code was 57% (1365) for code 199 "malignant neoplasm without specification of site;" 19% (448) for code 162.9"malignant neoplasm of trachea, bronchus, and lung, unspecified;" 13% (310) for code 163 "malignant neoplasm of pleura;" and 11% (271) for other codes. The CR (deaths) for the aforementioned three ICD-9 codes were 4.0% (1365/33,942), 0.3% (448/150,342), and 70.8% (310/438), respectively. Conclusions:The three ICD-9 codes (199, 162.9, and 163) were the most commonly used codes for MM and composed nine-tenths of all MM deaths in the years before the ICD-10 was introduced. Using only ICD-9 code 163, the code most often used as the surrogate measure of MM in mortality studies in the ICD-9 era, capture may have been only 13% of all MM deaths in the US, and the estimated number of MM deaths

How Malignant Mesothelioma Was Coded in Mortality Data in Taiwan During Years When the Specific ICD Code Was Not Available?

“…A recent study using DCMD for year 1996 in the United States indicated that the detection rate was 57%, 19%, and 13% for ICD‐9 code 199, 162.9, and 163, respectively; and the confirmation rate for the aforementioned three ICD‐9 codes were 4.0%, 0.3%, and 70.8%, respectively. 30 In our study, the detection and confirmation rates for ICD-9 code 163 in Taiwan were 18% and 14%, respectively, which are lower than those in other studies. One possible reason is that the Chinese-language terminology for the diagnosis of mesothelioma is “間皮瘤” and can be literally translated as “tumor between skins”; this translation is the potential reason why 11 deaths were coded with ICD-9 code 173 (other MN of skin).…”

Malignant mesothelioma among US Medicare beneficiaries: incidence, prevalence and therapy, 2016–2019

“…Because specific ICD-CM codes for malignant mesothelioma were not available prior to 2016 and ICD-9-CM surrogate codes for malignant mesothelioma substantially underestimate the mortality burden of mesothelioma, we began analysing claims starting in 2016 19 20. Therefore, annual calculations for the earlier years of this study period (ie, 2016 and 2017) are likely incomplete and may underestimate incidence and prevalence.…”

“…12 18 Medicare claims starting in 2016 were selected because 2016 was the first full year 10th Revision International Classification of Diseases, Clinical Modification (ICD-10-CM) diagnostic codes C45.0 (mesothelioma of pleura), C45.1 (mesothelioma of peritoneum), C45.2 (mesothelioma of pericardium), C45.7 (mesothelioma of other sites) and C45.9 (mesothelioma, unspecified) were used on Medicare claims. Ninth Revision (ICD-9-CM) codes were used on Medicare claims through September 2015 but specific ICD-9-CM codes for malignant mesothelioma were not available 19 20. Claims include ICD-10-CM diagnosis codes (up to 25 codes for institutional and up to 12 codes for non-institutional claims including a principal diagnosis code identifying the diagnosis chiefly responsible for the services provided) and may include additional healthcare procedure codes 12 21…”