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The objective was to compare two techniques to estimate age in databases with incomplete records and analyze their application to the calculation of cancer incidence. The study used the database of the Population-Based Cancer Registry from the city of São Paulo, Brazil, containing cases of urinary tract cancer diagnosed from 1997 to 2013. Two techniques were applied to estimate age: correction factor and multiple imputation. Using binomial distribution, six databases were simulated with different proportions of incomplete data on patient's age (from 5% to 50%). The ratio between the incidence rates was calculated, using the complete database as reference, whose standardized incidence was 11.83/100,000; the other incidence rates in the databases, with at least 5% incomplete data for age, were underestimated. By applying the correction factors, the corrected rates did not differ from the standardized rates, but this technique does not allow correcting specific rates. Multiple imputation was useful for correcting the standardized and specific rates in databases with up to 30% of incomplete data, but the specific rates for individuals under 50 years of age were underestimated. Databases with 5% incomplete data or more require correction. Although the implementation of multiple imputation is complex, it proved to be superior to the correction factor. However, it should be used sparingly, since age-specific rates may remain underestimated.

In clinical practice, recurrence of thrush is common in children living with HIV/AIDS. The aim of this study was to determine the factors associated with time spent free of oral candidiasis using survival analysis for recurrent events. A retrospective cohort study was carried out with 287 children treated between 1985 and 2009 at a reference center in the city of São Paulo, Brazil. The Prentice, Williams and Peterson model for recurrent events was used for the investigation of factors associated with the time free of oral candidiasis. The following factors were associated with the time patients were free of oral candidiasis: moderate immunodepression (HR = 2.5; p = 0.005), severe immunodepression (HR = 3.5; p < 0.001), anemia (HR = 3.3; p < 0.001), malnutrition (HR = 2.6; p = 0.004), hospitalization (HR = 2.2; p < 0.001), monotherapy (HR = 0.5; p = 0.006), dual therapy (HR = 0.3; p < 0.001) and triple therapy/highly active antiretroviral therapy (HR = 0.1; p < 0.001). The method analyzed in the present study proved useful for the investigation of recurrent events in patients living with HIV/AIDS.