No CoQ 4 U? CoQ10 and Hypertension
No CoQ 4 U? CoQ10 and Hypertension
Abstract & Commentary
By Russell Greenfield, MD
Synopsis: Results from this small intervention trial out of New Zealand strongly suggest that 200 mg/d of CoQ10 does not lower blood pressure in patients with metabolic syndrome and unsuccessfully treated hypertension.
Source: Young JM, et al. A randomized double-blind, placebo-controlled crossover study of coenzyme Q10 therapy in hypertensive patients with metabolic syndrome. Am J Hypertens 2012;25:261-270.
Coenzyme q10 (coq10) is considered an antioxidant with potential cardiovascular health benefits, especially in the setting of mild heart failure. A number of experts have also touted CoQ10 as a means of helping to control high blood pressure. The authors of this double-blind, placebo-controlled, 12-week crossover trial were interested in finding out whether CoQ10 would lower blood pressure (BP) in individuals previously diagnosed with metabolic syndrome and with poorly controlled BP despite active treatment with anti-hypertensive medication.
Subjects were recruited from general practitioners, research databases, and through advertisements in Christchurch, New Zealand. A total of 60 people were screened for entry, of which 31 (comprising the total number of hypertensive patients with metabolic syndrome in New Zealand kidding!) aged 25-75 years with hypertension (defined as average clinic SBP of > 140 mm Hg, or > 130 mm Hg for patients with type 2 diabetes) whose BP medication had not been changed over the prior month were enrolled. Almost all subjects were Caucasian (10% Maori). Exclusion criteria included uncontrolled hypertension (office BP > 160/100 mm Hg), type 1 diabetes, type 2 diabetes requiring insulin, hemoglobin A1c > 9%, BMI > 40 kg/m2 or an upper arm circumference > 42 cm, current smoking, warfarin treatment, or antioxidant vitamin supplementation, including CoQ10. Cardiovascular medications were not changed during the study period, and participants were asked to maintain their usual dietary and exercise practices.
Subjects were randomized to receive either CoQ10 100 mg twice daily or placebo for 12 weeks, followed by a 4-week washout period, and then received the alternative intervention for an additional 12 weeks. Participants and investigators were blinded to treatment allocation. Clinic and 24-h ambulatory BP measurements (determined at 20-minute intervals) were taken at baseline and at the end of both treatment periods. Blood for total CoQ10 levels, as well as other tests including cholesterol levels and CRP, was obtained. Primary outcome of interest was 12-week change in mean 24-h ambulatory SBP and DBP. Numerous secondary outcomes were followed and included 12-week change in 24-h mean arterial pressure (MAP), minimum and maximum BP and heart rate levels, morning surge and nocturnal fall in SBP and DBP, heart rate variability, clinic BP and heart rate, and plasma CoQ10 levels. For post-hoc subgroup analyses, the influence of potential mitigating factors including the presence of type 2 diabetes, cardiovascular disease, baseline ambulatory SBP and DBP levels, nocturnal BP dippers, treatment with specific medications including statins, metformin, and b-blockers, and attained levels of coenzyme Q10 were examined for primary and secondary outcomes.
There were no between group differences in baseline plasma CoQ10 levels before treatment (P = 0.18); plasma levels increased 3.7-fold after 12 weeks of therapy (P < 0.0001). However, no significant reductions were identified in mean 24-h SBP/DBP, 24-h pulse pressure, MAP, or heart rate following CoQ10 therapy compared with placebo. Similarly, no changes in mean clinic SBP/DBP after CoQ10 therapy were seen versus placebo. In addition, no significant effects occurred as a result of CoQ10 administration on mean daytime or nighttime BP (a small increase in daytime DBP occurred with placebo, P = 0.14), daytime or nighttime heart rate (though nighttime heart rate did increase significantly with placebo compared with CoQ10, P = 0.006), minimum and maximum day/nighttime BP readings (but there was an increase in minimum nighttime heart rate during placebo phase compared with CoQ10 phase of 2.7 vs. -0.4 beats/min, P < 0.05). A significant increase in clinic heart rate with placebo treatment was identified (P = 0.04). There were no significant differences in the 24-h average real variability for SBP/DBP or heart rate during CoQ10 vs placebo treatment. In the post-hoc subgroup analyses, there was no evidence of a treatment effect of CoQ10 on 24-h ambulatory BP parameters or heart rate when compared with placebo.
Compliance with the interventions was very high (> 95%), and CoQ10 was well tolerated with no serious adverse events being reported. The researchers concluded that CoQ10 in a daily dose of 200 mg should not be used as a complement to conventional antihypertensive therapy in patients with metabolic syndrome and inadequately controlled hypertension due to lack of effect.
Commentary
CoQ10 has been studied in-depth since the 1960s, and the accumulated data surrounding this antioxidant compound, also called ubiquinol for its seemingly universal presence in all cells of the body, is impressive if not always convincing. The majority of research involving CoQ10 has focused on cardiovascular disease, especially NYHA Class II-III heart failure where older studies, before the advent of a number of therapeutically effective heart medications currently in use, suggested significant clinical improvement in patients treated with CoQ10. A smattering of studies have also explored its use as a preventive against headaches, in the setting of breast cancer, as a means of enhancing gingival health and minimizing risk for statin-associated myopathy, and as a mild hypotensive agent. This latter area was the focus for the authors of the present study, and for good reasons existing data suggest low circulating levels of CoQ10 in the setting of hypertension (data referenced in article); CoQ10 appears to be safe and well tolerated when taken for long periods of time; it may lessen oxidative stress in the body (an issue for many patients including those with metabolic syndrome and hypertension); and administration has been associated with mild reductions in both SBP and DBP in some studies. Still, many have questioned the veracity of the conclusions drawn from some studies due to significant methodological shortcomings. In general, most experts feel there is promise but a defined benefit of CoQ10 on blood pressure is far from agreed upon.
The current study was well done and of adequate duration to identify an intervention effect. The CoQ10 product and dose employed were both good choices based on prior research, and the patient population was clearly in need of additional treatment (type and number of medications used detailed in paper). And yet, no significant therapeutic benefit was identified with CoQ10 administration. Is this result the death knell for CoQ10 as a treatment option for high blood pressure?
Not yet. Remember, prior studies have shown a mild blood pressure lowering effect from CoQ10, some of which included patients with very high BP, and there are always holes to poke in studies, including this one, though they are relatively few in number. The most glaring, small sample size, weakens any conclusions; compliance was measured by pill counts; and exclusion criteria would easily knock out many patients attending a primary care clinic.
People often stop taking their medications due to perceived side effects, a fact especially true in the setting of hypertension. Safe, effective options that are easy to take are highly desirable. Promising results from early studies with CoQ10 suggested it might be a part of the solution, but the current small yet well-done study does not support that conclusion. It is safe to say that CoQ10 should not be routinely considered in the complex management of people with inadequately treated high BP and the metabolic syndrome, the combination being a notoriously challenging clinical situation of increasing incidence, but these results also should not be interpreted as the final chapter regarding CoQ10's effectiveness as an adjunct in the management of hypertension in all circumstances.
Results from this small intervention trial out of New Zealand strongly suggest that 200 mg/d of CoQ10 does not lower blood pressure in patients with metabolic syndrome and unsuccessfully treated hypertension.Subscribe Now for Access
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