Home-to-hospital distance predicts mortality outcome for MI

18 August 2008

MedWire News: Distance from home to the nearest hospital may predict mortality outcome of patients experiencing a myocardial infarction (MI), say UK researchers.

They report in the journal Heart: After adjustment for rurality and other known risk factors, distance between home and admitting hospital was significantly associated with increased mortality both before hospital admission and after hospitalization." There was no effect of distance on in-hospital mortality.

Geographical inequalities are seen for hospital care in the UK, and, for patients with MI, this may be related to time to thrombolysis. Thomas MacDonald (Ninewells Hospital and Medical School, Dundee) and colleagues used the record-linkage database of the Medicines Monitoring Unit in Tayside, Scotland, to provide a study population of 347,131 people within an area of approximately 4600 square miles.

They determined primary certified cause of death of patients who died out of hospital, and all-cause mortality of admitted MI patients during hospital stay and following discharge from hospital.

Of 10,541 study patients who experienced an incident MI without previously being hospitalized for acute MI, 4133 died in the community. Of the 6408 admitted, 1010 died in hospital. The remaining 5398 patients were discharged, and 1907 died during the median 3.2-year follow-up.

Distance between home and the nearest possible hospital of admission was divided into tertiles of less than 3 miles, 3-9 miles, and over 9 miles. The respective estimated mean travel times by car were 5.9 minutes, 15.2 minutes, and 37.1 minutes.

For prehospital mortality, patients living 3-9 and over 9 miles from hospital had higher MI mortality than those under 3 miles from hospital, at adjusted odds ratios (OR)] of 1.46 and 2.05, respectively.

The age-adjusted death rate for hospitalized patients was 11.6%; no relationship was seen between risk for death in hospital and distance between home and hospital.

For follow-up mortality, the age-adjusted death rate was 8.6%. Those who lived more than 9 miles from hospital had an increased risk for mortality during follow-up relative to those within 3 miles (adjusted hazard ratio [HR]=1.90).

In their subgroup analysis of 209 follow-up patients with thrombolysis data, the authors note that this "suggested that early thrombolysis reduced mortality (adjusted HR=0.63)."

In addition, the researchers say: "Further studies are needed to explore the reasons for this association."

Heart 2008; 94: 1141-1146