A medical device, comprising: a signal analyzer circuit, including: a patient status input unit configured to receive at least a first chronic condition indicator and a second chronic condition indicator of a patient non-identical to the first chronic condition indicator, the first and second chronic condition indicators each indicating sustained medical status of the patient that does not change or changes slowly over time; a signal receiver circuit configured to receive one or more physiologic signals of the patient; a signal metrics generator circuit configured to generate a plurality of signal metrics from the one or more physiologic signals, the plurality of signal metrics including a first set of one or more signal metrics generated in response to the first chronic condition indicator meeting at least one first specified criterion, and a second set of signal metrics generated in response to the second chronic condition indicator meeting at least one second specified criterion, wherein the first set is associated with the first chronic condition indicator and the second set is associated with the second chronic indicator; and a patient-specific signal metric selector circuit configured to select a subset of patient-specific signal metrics from the first and second sets of signal metrics using signal metric performance measures of at least one metric from the first and second sets of signal metrics; and a risk stratification circuit configured to generate a composite risk index using the selected subset of patient-specific signal metrics, the composite risk index indicative of the probability of the patient later developing an event indicative of worsening of heart failure. a patient status input unit configured to receive at least a first chronic condition indicator and a second chronic condition indicator of a patient non-identical to the first chronic condition indicator, the first and second chronic condition indicators each indicating sustained medical status of the patient that does not change or changes slowly over time; a signal receiver circuit configured to receive one or more physiologic signals of the patient; a signal metrics generator circuit configured to generate a plurality of signal metrics from the one or more physiologic signals, the plurality of signal metrics including a first set of one or more signal metrics generated in response to the first chronic condition indicator meeting at least one first specified criterion, and a second set of signal metrics generated in response to the second chronic condition indicator meeting at least one second specified criterion, wherein the first set is associated with the first chronic condition indicator and the second set is associated with the second chronic indicator; and a patient-specific signal metric selector circuit configured to select a subset of patient-specific signal metrics from the first and second sets of signal metrics using signal metric performance measures of at least one metric from the first and second sets of signal metrics; and a risk stratification circuit configured to generate a composite risk index using the selected subset of patient-specific signal metrics, the composite risk index indicative of the probability of the patient later developing an event indicative of worsening of heart failure.