Differences in the causes of death of HIV-positive patients in a cohort study by data sources and coding algorithms.

OBJECTIVES: To compare causes of death (CoDs) from two independent sources: National Basic Death File (NBDF) and deaths reported to the Spanish HIV Research cohort [Cohort de adultos con infección por VIH de la Red de Investigación en SIDA CoRIS)] and compare the two coding algorithms: International Classification of Diseases, 10th revision (ICD-10) and revised version of Coding Causes of Death in HIV (revised CoDe). METHODS: Between 2004 and 2008, CoDs were obtained from the cohort records (free text, multiple causes) and also from NBDF (ICD-10). CoDs from CoRIS were coded according to ICD-10 and revised CoDe by a panel. Deaths were compared by 13 disease groups: HIV/AIDS, liver diseases, malignancies, infections, cardiovascular, blood disorders, pulmonary, central nervous system, drug use, external, suicide, other causes and ill defined. RESULTS: There were 160 deaths. Concordance for the 13 groups was observed in 111 (69%) cases for the two sources and in 115 (72%) cases for the two coding algorithms. According to revised CoDe, the commonest CoDs were HIV/AIDS (53%), non-AIDS malignancies (11%) and liver related (9%), these percentages were similar, 57, 10 and 8%, respectively, for NBDF (coded as ICD-10). When using ICD-10 to code deaths in CoRIS, wherein HIV infection was known in everyone, the proportion of non-AIDS malignancies was 13%, liver-related accounted for 3%, while HIV/AIDS reached 70% due to liver-related, infections and ill-defined causes being coded as HIV/AIDS. CONCLUSION: There is substantial variation in CoDs in HIV-infected persons according to sources and algorithms. ICD-10 in patients known to be HIV-positive overestimates HIV/AIDS-related deaths at the expense of underestimating liver-related diseases, infections and ill defined causes. CoDe seems as the best option for cohort studies.

Accurately estimating breast cancer survival in Spain: cross-matching local cancer registries with the National Death Index.

OBJECTIVES: To assess the impact of using data from the National Death Index (NDI) of Spain to estimate breast cancer survival rates among residents of Girona and Zaragoza diagnosed in 1995-1999. METHODS: This was an observational, longitudinal epidemiologic study, using two population-based cancer registries. Data collected were of female residents of Girona or Zaragoza who had been diagnosed with breast cancer in 1995-1999. Observed and relative 5-year survival rates were estimated, first using the information available from the Girona and Zaragoza cancer registries, and then with the inclusion of NDI data. The 5-year relative survival rate and corresponding 95% Confidence Intervals were estimated using the Hakulinen method. The Kaplan-Maier method and Log Rank test were used to compare survival curves. RESULTS: No statistically significant difference in survival curves was observed in Girona for the data obtained before and after cross-matching with the NDI. However, there was a significant difference in Zaragoza. A comparison of the relative survival rates of each of the two registries before NDI cross-matching showed differences of 3.9% (5-year) and 16.1% (10-year) between the two, whereas after the cross-match, the difference was only 0.5% (5-year) and 1.2% (10-year). CONCLUSIONS: In Spain it is imperative that there be systematic use of NDI data to supplement cancer registries, so that comparisons of relative survival rates between registries can be improved.

Accurately estimating breast cancer survival in Spain: cross-matching local cancer registries with the National Death Index / Estimación precisa de la supervivencia de cáncer de mama en España: emparejamiento de los registros locales de cáncer con el Índice Nacional de Defunciones

OBJECTIVES: To assess the impact of using data from the National Death Index (NDI) of Spain to estimate breast cancer survival rates among residents of Girona and Zaragoza diagnosed in 1995-1999. METHODS: This was an observational, longitudinal epidemiologic study, using two population- based cancer registries. Data collected were of female residents of Girona or Zaragoza who had been diagnosed with breast cancer in 1995-1999. Observed and relative 5-year survival rates were estimated, first using the information available from the Girona and Zaragoza cancer registries, and then with the inclusion of NDI data. The 5-year relative survival rate and corresponding 95 percent Confidence Intervals were estimated using the Hakulinen method. The Kaplan-Maier method and Log Rank test were used to compare survival curves. RESULTS: No statistically significant difference in survival curves was observed in Girona for the data obtained before and after cross-matching with the NDI. However, there was a significant difference in Zaragoza. A comparison of the relative survival rates of each of the two registries before NDI cross-matching showed differences of 3.9 percent (5-year) and 16.1 percent (10-year) between the two, whereas after the cross-match, the difference was only 0.5 percent (5-year) and 1.2 percent (10-year). CONCLUSIONS: In Spain it is imperative that there be systematic use of NDI data to supplement cancer registries, so that comparisons of relative survival rates between registries can be improved.

OBJETIVO: Evaluar el efecto de utilizar los datos del Índice Nacional de Defunciones (IND) de España para estimar las tasas de supervivencia de cáncer de mama en las mujeres residentes en Girona y Zaragoza que recibieron el diagnóstico de cáncer de mama en 1995-1999. MÉTODOS: Se realizó un estudio epidemiológico observacional y longitudinal basado en el empleo de los registros de cáncer de mujeres residentes en Girona y Zaragoza que habían recibido el diagnóstico de cáncer de mama en 1995-1999. Se estimaron las tasas de supervivencias observada y relativa a 5 años, primero según la información disponible en los registros de cáncer de Girona y Zaragoza y luego con la inclusión de los datos del IND. Se calcularon las tasas de supervivencia relativa a 5 años y sus correspondientes intervalos de confianza de 95 por ciento por el método de Hakulinen. Las curvas de supervivencia se compararon por el método de Kaplan-Maier y la prueba de rangos logarítmicos. RESULTADOS: No se encontraron diferencias estadísticamente significativas entre las curvas de supervivencia de Girona antes y después de emparejar lo datos locales con los del IND; sin embargo, hubo diferencias significativas entre las curvas de Zaragoza. Al comparar las tasas de supervivencia relativa de cada uno de los registros antes de emparejarlos con los datos del IND se encontraron diferencias de 3,9 por ciento (a 5 años) y 16,1 por ciento (a 10 años), mientras que después del emparejamiento, la diferencia entre ellas fue solamente de 0,5 por ciento (a 5 años) y 1,2 por ciento (a 10 años). CONCLUSIONES: En España es imperativo el empleo sistemático de los datos del IND para complementar los registros de cáncer de manera de mejorar las comparaciones de las tasas de supervivencia relativa cuando se utilizan diferentes registros.