Layton JB, Li W, Wang L, Yuan J, Gilman JP, Horton DB, Setoguchi S. Heatwaves and heat-sensitizing medications in vulnerable older adults. Presented at the 35th Annual ICPE Conference; August 28, 2019. Philadelphia, PA. [abstract] Pharmacoepidemiol Drug Saf. 2019 Aug 20; 28(S2):870. doi: 10.1002/pds.4864.


BACKGROUND: Heatwaves kill people and have become more common and severe. Some medications may sensitize fragile patients with chronic conditions to heatwaves.

OBJECTIVES: To determine if heat‑sensitizing medications increase the risk of heat‑related hospitalization during the warm summer months in the

METHODS: Linking 20% US Medicare Part A, B, and D data with daily maximum surface air temperature (tasmax) using residence ZIP codes, we identified pa chronic kidney disease (CKD), diabetes on chronic insulin use (DM), COPD, dementia, heart failure (HF), myocardial infarction (MI), and stroke during June‑Au 2007‑2012. We assessed exposure to angiotensin blockers (ACE/ARB), loop diuretics (LD), antipsychotics (AP), beta blockers (BB), and anticholinergic agen defined heatwaves as at least two consecutive days with tasmax > 95 th percentile. We assessed heat‑related hospitalizations (heat exhaustion, heat fatigue dehydration, hyperosmolality, or excessive exertion) during follow‑up. We conducted self‑controlled case series analysis for censored or curtailed data to e ratios (RR) and 95% confidence intervals (CI) for heat wave and medication effects. We evaluated each medication separately, both overall in the full cohort disease‑specific cohort.

RESULTS: Among 377,100 patients (73% female; 80% white; mean age=80, SD 8; 41% living in South region; 42% CKD, 29% dementia, 26% HF, 19% DM, 12% 7% stroke), 33% experienced a heatwave. A heat‑related hospitalization occurred in 11,244 (3%). Heatwaves were associated with modest increases in he hospitalizations (RR 1.1 [1.0‑1.2]). Medication exposure varied widely ranging from 9% (AP) to 75% (AC). After accounting for heatwaves, several dryg classe increased risk for heat‑related hospitalizations except for AC and AP: BB, 1.3 (1.1‑1.6); LD, 1.4 (1.2, 1.7) and ACE/ARB RR=1.6 (1.3‑1.9). The effects of ACE were pronounced in subgroups with CKD, DM, and HF, with RR >5 and lower CI bound > 2.

CONCLUSIONS: Many of the heat‑sensitizing medications increased the risk of heat‑related hospitalizations among older patients with chronic disease. ACE greater risks in subgroups with CKD, DM, and HF. Large high‑resolution cohort studies are needed to understand the interactions between heatwaves and m heat‑related hospitalizations and other health outcomes in vulnerable older adults.

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