The quality of evidence is downgraded by indirectness (differences between the population and outcomes of interest and those studied: only short-term outcomes reported in adolescents with recently diagnosed mild hypertension), and by imprecise results (few patients).
A Cochrane review included 1 crossover study with 30 subjects. The aim of this review was to determine whether or not treatment for hyperuricemia also results in a reduction of blood pressure (BP) in hypertensive patients. The study randomized 30 adolescents (11-17 years), newly diagnosed stage 1 primary hypertension and with serum uric acid (SUA) > 6mg/dl, to receive allopurinol 200 mg twice daily for 4 weeks, and placebo for 4 weeks, with a 2 week washout period between treatments. During the allopurinol phase, blood pressure decreased more than during placebo phase. (Table ). As expected, SUA decreased from 7.0 (6.5 - 7.5) to 4.2 (3.7 - 4.6) mg/dL after treatment with allopurinol, in contrast with the control group (6.2. and 6.4 mg/dL at the beginning of placebo phase and after four weeks, respectively). No side effects were seen in patients treated with allopurinol.
| Outcome | Participants (studies) | Placebo | Allopurinol | P-value |
|---|---|---|---|---|
| Change in systolic casual blood pressure | 30 (1) | - 2.0 mmHg (0.3 to - 4.3 mmHg) | - 6.9 mmHg (- 4.5 to - 9.3 mmHg) | 0.009 |
| Change in diastolic casual blood pressure | 30 (1) | - 2.4 mmHg (0.2 to - 4.1 mmHg) | - 5.1 mmHg (- 2.5 to - 7.8 mmHg) | 0.05 |
| Change in systolic ambulatory blood pressure | 30 (1) | 0.8 mmHg (3.4 to - 2.9 mmHg) | - 6.3 mmHg (- 3.8 to - 8.9 mmHg) | 0.001 |
| Change in diastolic ambulatory blood pressure | 30 (1) | - 0.3 mmHg (2.3 to - 2.1 mmHg) | - 4.6 mmHg (- 2.4 to - 6.8 mmHg) | 0.004 |
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