Paddy Farrington | Search PubMed

PubMed2004

Risk of myocardial infarction and stroke after acute infection or vaccination.

BACKGROUND: There is evidence that chronic inflammation may promote atherosclerotic disease. We tested the hypothesis that acute infection and vaccination increase the short-term risk of vascular events. METHODS: We undertook within-person comparisons, using the case-series method, to study the risks of myocardial infarction and stroke after common vaccinations and naturally occurring infections. The study was based on the United Kingdom General Practice Research Database, which contains computerized medical records of more than 5 million patients. RESULTS: A total of 20,486 persons with a first myocardial infarction and 19,063 persons with a first stroke who received influenza vaccine were included in the analysis. There was no increase in the risk of myocardial infarction or stroke in the period after influenza, tetanus, or pneumococcal vaccination. However, the risks of both events were substantially higher after a diagnosis of systemic respiratory tract infection and were highest during the first three days (incidence ratio for myocardial infarction, 4.95; 95 percent confidence interval, 4.43 to 5.53; incidence ratio for stroke, 3.19; 95 percent confidence interval, 2.81 to 3.62). The risks then gradually fell during the following weeks. The risks were raised significantly but to a lesser degree after a diagnosis of urinary tract infection. The findings for recurrent myocardial infarctions and stroke were similar to those for first events. CONCLUSIONS: Our findings provide support for the concept that acute infections are associated with a transient increase in the risk of vascular events. By contrast, influenza, tetanus, and pneumococcal vaccinations do not produce a detectable increase in the risk of vascular events.

Acute Disease↗

PubMed2003

Exposure to tricyclic and selective serotonin reuptake inhibitor antidepressants and the risk of hip fracture.

The use of tricyclic antidepressants is associated with an increased risk of hip fracture. Despite a better side effect profile, this adverse effect has also been reported for selective serotonin reuptake inhibitors. To determine whether these findings result from bias arising from the case-control method, the authors have performed a case-control analysis and a self-controlled case-series analysis using 1987-1999 diagnosis data for 16,341 cases of hip fracture and 29,889 controls drawn from the United Kingdom General Practice Research Database. Both analyses showed an association between hip fracture and antidepressant treatment, and this was most marked during the first 15 days of treatment. The estimates from the case-control study were larger than those from the case-series analysis: The odds ratios for fracture within the first 15 days of a prescription for tricyclic antidepressants and serotonin reuptake inhibitors were 4.76 (95% confidence interval (CI): 3.06, 7.41) and 6.30 (95% CI: 2.65, 14.97), whereas the equivalent incidence ratios were 2.30 (95% CI: 1.82, 2.90) and 1.96 (95% CI: 1.35, 2.83). Tricyclic antidepressants and serotonin reuptake inhibitors are both associated with an independent increase in hip fracture incidence during the first weeks of treatment. The estimates from the case-series analyses were smaller than those from the case-control analyses, suggesting that the case-control method is subject to bias.

Aged↗

PubMed2003

Clinical trials.

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Clinical Protocols↗