Objective: To analyze the impact of the length of disease-free intervals on incidence estimation.
Data source: Statutory health insurance sample in Germany.
Study design: Overestimation of the incidence in the first quarter of 2008 for three selected diseases, diabetes mellitus, colorectal cancer, and heart failure, depending on different lengths of preceding disease-free intervals.
Data collection/extraction methods: Continuously insured from 2000 until 2008 ≥ 18 years (N = 144,907).
Principal findings: Compared with an 8-year disease-free period, incidence overestimations for diabetes, colorectal cancer, and heart failure were 40, 23, and 43 percent defining a 1-year, and 5, 9, and 5 percent defining a 5-year disease-free period, respectively.
Conclusions: Depending on the specific disease, caution has to be taken while using short disease-free periods because incidence estimates may be extremely overestimated.