Introduction: Current methods for assessing adherence to combination therapy based on aggregated measures (e.g., PDC, proportion of days covered) poorly capture treatment intensity and sustainability over time. We attempted to describe adherence trajectories for combination therapy using integral metrics. Aim: To develop a set of integral metrics analogous to key pharmacokinetic (PK) parameters – area under the concentration-time curve ( AUC , area under the curve), maximum concentration ( C max