An adherent device to monitor a patient comprises an adhesive patch to adhere to a skin of the patient. At least four electrodes are connected to the patch and capable of electrically coupling to the patient. Impedance circuitry is coupled to the at least four electrodes to measure a hydration signal of the patient. Electrocardiogram circuitry is coupled to at least two of the at least four electrodes to measure an electrocardiogram signal of the patient. An accelerometer can be mechanically coupled to the adhesive patch to generate a signal in response to at least one of an activity or a position of the patient.