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Bed rest after heart attack

Systematic review
Results
Comment

How long should someone stay in bed after an uncomplicated heart attack? Guidelines from cardiologists in the USA and Europe recommend at least 12 hours bed rest in such patients. The reasons for bed rest include reduced workload on the heart, avoiding poor perfusion and possible further damage to the myocardium. But if patients stay immobile for too long, they may be at increased risk of thromboembolic complications. A systematic review of controlled trials [1] tells us that longer bed rest is no better than shorter bed rest, but may leave a few unanswered questions.

Systematic review

Searching involved six electronic databases, as well as textbooks and reference articles. For inclusion patients had to have uncomplicated myocardial infarction, and be controlled studies (randomised or quasi-randomised) of shorter versus longer periods of bed rest. Various endpoints were used, including mortality, angina pectoris, reinfarction and thromboembolic events.

Results

There were 15 studies, the earliest published in 1954 and the most recent in 1989; most were published in the 1970s. Oral anticoagulants were used in six studies and thrombolysis in one. The mean age in the studies ranged between 52 and 67 years, with women representing 9% to 28% of patients. The shorter duration of bed rest varied between two and 14 days, and the longer between five and 40 days. Follow up times were varied, between five days and a year.

For no outcome was shorter bed rest any different than longer bed rest (Table 1). Mortality, angina, reinfarction and venous thrombosis all had relative risks that included 1, indicating no significant difference between treatments.


Table 1: Major outcomes after shorter versus longer periods of bed rest after uncomplicated myocardial infarction (all trials)


Number of
Percent mortality
Trial description
Trials
Patients
Shorter
Longer
Relative risk
(95% CI)
All trials
13
2496
10
11
0.9 (0.7 to 1.2)
Randomisation unequivocal
4
931
5
5
0.9 (0.5 to 1.6)
Randomisation stated
8
1389
9
9
0.9 (0.7 to 1.3)
Short rest less than 7 days
9
1882
9
9
1.0 (0.8 to 1.4)
Anticoagulants used
7
1663
10
9
1.0 (0.7 to 1.3)


Most information was for mortality, where there were consistent results in 13 trials (Figure 1). For this outcome it was possible to perform sensitivity analyses. No sensitivity analysis produced any different result, using only those trials unequivocally properly randomised, or including those where the method of randomisation was not stated, or trials where the shorter period of bed rest was less than seven days, or those where anticoagulants or thrombolysis was used (Table 2).


Figure 1: Individual trials of shorter versus longer bed rest






Table 2: Mortality after shorter versus longer periods of bed rest after uncomplicated myocardial infarction, sensitivity analysis by trial type


Number of
Percent mortality
Outcome
Trials
Patients
Shorter
Longer
Relative risk
(95% CI)
Mortality
13
2496
10
11
0.9 (0.7 to 1.2)
Angina pectoris
7
1865
7
7
1.0 (0.7 to 1.4)
Reinfarction
11
2372
9
8
1.1 (0.9 to 1.5)
Venous thrombosis
6
755
6
8
0.8 (0.4 to 1.3)


Comment

Trials were old, many were small, and some had problems with quality that could lead to potential bias. Yet for different outcomes, and using sensitivity analysis, no benefit of longer over shorter bed rest was found. Unless there are compelling reasons, there would seem to be no need to spend many days in bed after an uncomplicated heart attack.

Reference:

  1. H Herkner et al. Short versus prolonged bed rest after uncomplicated acute myocardial infarction: a systematic review and meta-analysis. Journal of Clinical Epidemiology 2003 56: 775-781.

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