[Enrichment of Claims Data with Official Causes of Death Using a Record Linkage with the Epidemiological Cancer Registry of North Rhine-Westphalia: Feasibility Study and Comparison of Procedures]. / Anreicherung eines GKV-Datensatzes mit amtlichen Todesursachen über einen Abgleich mit dem Epidemiologischen Krebsregister Nordrhein-Westfalen: Machbarkeitsstudie und Methodenvergleich.

BACKGROUND: Claims data of the statutory health insurance (SHI) are an important data source for the evaluation of cancer prevention programs. However, this source does not contain relevant information on cause of death. This study examined whether individual claims data can be enriched with data on the required cause of death using record linkage procedures with suitable external data sources. METHODS: In the German pharmacoepidemiologic research database (GePaRD) we identified a sample of 25,528 deceased female residents of North Rhine Westphalia (NRW) who, according to GePaRD information, died between 2006 and 2013. Date and cause of all deaths among inhabitants of NRW since 2005 were available in the epidemiological cancer registry of NRW. In cooperation with 2 SHI companies, we tried to match each individual of the sample with a case of death in NRW and the corresponding cause of death using a probabilistic and, alternatively, a deterministic linkage procedure. RESULTS: Of the study sample, 94.72% were successfully matched by the probabilistic and 93.36% by the deterministic method. CONCLUSIONS: The probabilistic and the deterministic record linkage approach produced comparably high matching rates. Cases without matches are probably due to errors occurring at the stage of personal data entry. Given the lower technical efforts, the deterministic approach appears to be the method of choice for the enrichment of claims data with cause of death information from suitable external data sources in Germany.

Digital mammography screening in Germany: Impact of age and histological subtype on program sensitivity.

INTRODUCTION: Program sensitivity (PS), i.e., the ratio of screen-detected cancers divided by the sum of screen-detected plus interval cancers, is a major outcome in population-based mammography screening programs (MSP). This study evaluated PS within the digital MSP in Germany focussing on the impact of age and histological subtype. METHODS: Data of 838,579 first-time participants aged 50-69 years who were screened in 2005-2008 were linked with cancer registry data from Germany's most populous state, North Rhine-Westphalia. Invasive breast cancers and ductal carcinomas in situ (DCIS) were detected either at screening or during the 24 month post-screening interval. PS was evaluated with respect to age at screening, in-situ or invasive cancer and histological characteristics. RESULTS: In total, 6767 cancers were detected at screening and 1884 cancers were diagnosed during the post-screening interval. The overall PS amounted to 78.2% and increased from 72.1% at age 50-54 years to 82.4% at age 65-69 years (p for trend <0.0001). PS was higher for non-lobular (79.1%) than lobular carcinomas (72.1%, p < 0.0001). The highest PS was observed in DCIS across all ages (>90%), while PS was lowest among participants aged 50-54 years with invasive breast cancer (67.7%), particularly among those with lobular subtype (62.8%). Interval cancers showed generally more advanced tumour stages. CONCLUSIONS: While overall PS was high, differences across subgroups indicated that youngest screening participants are at higher risk of interval cancer. Age-adapted recall and assessment strategies in younger participants may need to be considered to improve PS in younger women.

The incidence of interval cancers in the German mammography screening program: results from the population-based cancer registry in North Rhine-Westphalia.

BACKGROUND: Cancer screening programs must meet high standards for quality and effectiveness, because many healthy persons need to be screened to detect relatively few cases of cancer. In this study, we use the rate of interval cancers as an important surrogate indicator for evaluating the German mammography screening program (MSP). METHODS: All first-time participants in the MSP in the German federal state of North Rhine-Westphalia over the period 2005-2008 whose screening mammogram had been read as negative were followed over the next 24 months for the potential development of breast cancer (an "interval cancer" or IC). The screening data in the MSP database were compared in anonymized fashion with reports of cancer that were recorded at the Epidemiological Cancer Registry North Rhine-Westphalia. RESULTS: Among the 878,764 women with negative screening mammograms in the first screening round, 2036 (23.2 per 10,000) developed an IC in the ensuing 24 months. These ICs accounted for 40% of all T2-T4 breast cancers occurring in first-time participants in the screening program in the 2 years after screening. The relative rate of IC compared to the background incidence of breast cancer before introduction of the MSP was 27% in the first year and 58% in the second. Screening detected 78% of all breast cancers that occurred during a maximum of 2 years after screening. CONCLUSION: The IC rates in the implementation phase of the MSP agree with those found in other, established European programs. The present study is the first one to assess this important surrogate parameter to characterize the effectiveness of the German MSP among women in North Rhine-Westphalia, Germany's largest state by population.