Purpose: To evaluate the impact of optimal treatment guidelines for the combined management of hyperlipidemia and hypertension for patients with type 2 diabetes.
Method: We developed a Markov decision process (MDP) model to determine the optimal start times for combined cholesterol and blood pressure medications for patients with type 2 diabetes. Health states were defined by cholesterol, blood pressure, hemoglobin A1c, and the static risk factors race, smoking status, and sex used by the United Kingdom Prospective Diabetes Study risk model. Transition probabilities and treatment effects are estimated from a longitudinal clinical dataset. Cost parameters are taken from secondary sources. The objective of the optimal guideline is to maximize expected benefits over the course of the patient’s lifetime. Benefits are defined by the difference in increased quality-adjusted life years (QALYs), based on a societal willingness-to-pay factor, minus costs of medication, treatment and long term care for CHD and stroke.
Result: We compute the optimal combined hypertension and hyperlipidemia treatment guidelines based on our MDP model. We compare the optimal guidelines to a simulation of a combination of the U.S. ATPIII and JNC7 guidelines to estimate the difference in expected QALYs and total discounted lifetime healthcare costs starting at age 40. For a willingness-to-pay of U.S. $100,000/QALY we find that the optimal guidelines outperform the ATPIII and JNC7 guidelines by adding an average of 0.049 QALYs for male patients and 0.166 QALYs for female patients and by lowering the lifetime costs by an average of $8,844 for male patients and $7,223 for female patients. The optimal guidelines suggested that patients in all health states should initiate statins. However, initiating and intensifying hypertension treatment varied based on health state and gender. The U.S. guidelines called for more intensive treatment of high blood pressure with a greater number of blood pressure medications being recommended; in addition, initiation of medications occurred earlier in life than with the optimal guidelines.
Conclusion: Using the ATPIII and JNC7 guidelines results in lower QALYs at increased costs for both males and females, compared to our optimal guidelines. The optimal guidelines would improve the efficiency of U.S. guidelines by providing large savings in both QALYs and costs at the population level.
Candidate for the Lee B. Lusted Student Prize Competition