Supine Systolic Blood Pressure and 1-Year Mortality in Patients With Acute Chest Pain

To the Editor: Dr Stenestrand and colleagues¹ analyzed data from 119 151 participants in the Registry of Information and Knowledge About Swedish Heart Intensive Care Admissions (RIKS-HIA) who were treated for chest pain in the intensive care unit from 1997 to 2007. The study reported that absolute 1-year mortality was 40.3% higher in quartile 1 (Q1, supine systolic blood pressure <128 mm Hg) compared with quartile 2 (Q2, supine systolic blood pressure 128-144 mm Hg), adjusted for age; sex; smoking status; diastolic blood pressure; use of antihypertensive medication and nitroglycerin at admission; and use at discharge of antihypertensive, statin, antiplatelet, and anticoagulant drugs and other lipid-lowering medication. As a study limitation, the authors said that “it is possible that factors not present in the RIKS-HIA database, such as malnutrition or anemia, might explain part of the relatively poor prognosis associated with low admission systolic BP.”¹ However, another possible confounder is sleep apnea, an important pathophysiological and prognostic factor in cardiovascular disease.^2- 5