In some examples, a system comprises one or more medical devices configured to, for each of a plurality of periods, determine a respective value for each of a plurality of parameters of a patient and processing circuitry. The processing circuitry can for each of the plurality of periods, execute an algorithm to determine at least one of a heart failure risk score or status for the patient based on the determined values for the period, determine a number of the determined heart failure risk scores or statuses that were false determinations, determine that the number of false determinations for the patient satisfies a false determination threshold, and modify the algorithm for the patient in response to the determination that the number of false determinations for the patient satisfies the false determination threshold.
