Abstract P176: Impact of Serious Adverse Event Risks on the Cost-effectiveness of Intensive Blood Pressure Goals in Patients Aged ≥75 Years

Abstract

Background: Compared to the overall Systolic Blood Pressure Intervention Trial (SPRINT) results, patients aged ≥75 years at baseline had a greater reduction in cardiovascular disease (CVD) events and all-cause mortality with an intensive systolic blood pressure (SBP) goal (<120 mmHg) compared to a standard SBP goal (<140 mmHg). Applying an intensive SBP goal in high-risk older patients represents a major shift in clinical practice and may increase concern for medication-related severe adverse events (SAEs). We hypothesized that the benefits of reduced CVD risk would outweigh the increased costs and SAE risk of intensive vs. standard SBP goals in SPRINT-eligible patients aged ≥75 years even when considering variable SAE risks. Methods: A microsimulation health-state transition model of 10,000 patients was created to estimate the CVD events, SAEs, quality-adjusted life years (QALYs), and direct healthcare costs of intensive vs. standard SBP goals. The model assumed patients were adherent to treatment during the median SPRINT follow-up, but that all patients would become non-adherent over 5 years. While adherent, CVD and SAE risks were derived from published SPRINT effect estimates for the ≥75 subgroup. Due to uncertainty in the SAE risk associated with intensive SBP goals in older adults, the intensive arm SAE risk was varied to determine the point at which treatment costs and harms outweighed CVD benefits at accepted willingness-to-pay thresholds. Healthcare costs and health state utilities were derived from national sources and other published estimates. Results: If SAE risk was equal to the observed rates in SPRINT, mean lifetime costs and QALYs were $268,000 and 7.85 for the intensive arm, and $262,000 and 7.60 for the standard arm. The resulting incremental cost-effectiveness ratio (ICER) was about $26,000 per QALY gained. However, as SAE risk in the intensive arm increased by 1.5, 2, and 2.5 times, the ICER increased to $33,000, $43,000, and $55,000 per QALY gained, respectively. Conclusion: Intensive SBP goals may be a cost-effective way to reduce CVD events and improve survival in patients aged ≥75 years, but safety and cost-effectiveness depend on medication-related SAE risk. However, these results are based on summary data and do not account for clustering of risks at the individual patient level. Thus, more precise prediction of risks and benefits is needed to guide selection of older patients for intensive SBP treatment goals.