Aspirin prophylaxis in patients at low risk for cardiovascular disease: a systematic review of all-cause mortality - Original Research

Journal of Family Practice, August, 2002 by John M. Boltri, Mark R. Akerson, Robert L. Vogel

TABLE 1
Characteristics of aspirin studies
that included low-risk subjects

                                    USPHS                BDS

Trial                              Steering              Peto
                                Committee (20)        et al (21)
Study population                  Healthy US          Healthy UK
                                  physicians          physicians
Study type                        Randomized          Randomized
                               controlled trial    controlled trial
Subjects in
  aspirin group                     11,037               3429
Subjects in
  control group                     11,034               1710
Treatment                       325 mg aspirin         500 mg/d
                               every other day         aspirin
Comparison                         Placebo            No aspirin
Follow-up time (y)                    5                   6
Jadad score
  Randomization ([dagger])            1                   2
  Blinding ([double dagger])          1                   0
  Withdrawals ([section])             1                   0
  Total                               3                   2
Significant difference                No                  No
   in mortality

                                     NHS

Trial                               Manson
                                  et al (22)
Study population                  Healthy US
                                    nurses
Study type                          Cohort
Subjects in
  aspirin group                     35,048
Subjects in
  control group                     52,630
Treatment                        1-15 aspirin
                                  tablets/wk
Comparison                           None
Follow-up time (y)                    6
Jadad score
  Randomization ([dagger])           NA *
  Blinding ([double dagger])          NA
  Withdrawals ([section])             NA
  Total                               NA
Significant difference           Yes in favor
    in mortality                 of no aspirin

* The Jadad scale does not apply to cohort studies.

([dagger]) Two points maximum.

([double dagger]) Two points maximum.

([section]) One point maximum.

BDS, British Doctors Study; NA, not applicable; NHS,
Nurses Health Study, USPHS. US
Physicians Health Study.
TABLE 2
Rates of myocardial infarction, stroke,
total cardiovascular mortality, and total
mortality in studies of aspirin vs no aspirin
that included low-risk patients

                                         Study

Outcome                    USPHS (5 y)         BDS (6 y)

Myocardial infarction
 Aspirin, n (%)             139 (1.26)         169 (4.93)
 No aspirin, n (%)          239 (2.17)         88 (5.151
 OR (CI)                 0.58 (0.47-0.71)   0.96 (0.73-1.24)

Stroke
 Aspirin, n (%)             119 (1.08)         91 (2.65)
 No aspirin, n (%)          98 (0.89)          39 (2.28)
 OR (CI)                 1.22 (0.93-1.59)   1.17 (0.80-1.71)

Total cardiovascular
 mortality
 Aspirin, n (%)             81 (0.73)          148 (4.32)
 No aspirin, n (%)          83 (0.75)          79 (4.62)
 OR (CI)                 0.98 (0.72-1.33)   0.93 (0.70-1.23)

Total mortality
 Aspirin, n (%)             217 (1.97)         270 (7.87)
 No aspirin, n (%)          227 (2.06)         151 (8.83)
 OR (CI)                 0.95 (0.79-1.15)   0.88 (0.72-1.09)

                              Study

Outcome                     NHS (6 y)

Myocardial infarction
 Aspirin, n (%)             244 (0.70)
 No aspirin, n (%)          157 (0.30)
 OR (CI)                 2.34 (1.92-2.86) *

Stroke
 Aspirin, n (%)             109 (0.31)
 No aspirin, n (%)          89 (0.17)
 OR (CI)                 1.84 (1.39-2.44) *

Total cardiovascular
 mortality
 Aspirin, n (%)             68 (0.19)
 No aspirin, n (%)          62 (0.12)
 OR (CI)                 1.65 (1.17-2.33) *

Total mortality
 Aspirin, n (%)             354 (1.01)
 No aspirin, n (%)          292 (0.55)
 OR (CI)                 1.83 (1.57-214) *

* OR significant at the .05 level.
BDS, British Doctors Study, CI, 95% confidence interval;
n (%), number (percentage) of
patients taking or not taking aspirin; NHS, Nurses Health Study;
OR, odds ratio; USPHS, US Physicians Health Study.