Fibromyalgia and nondipper circadian blood pressure variability

Aberrant circadian rhythm with persistent nocturnal sympathetic hyperactivity has pointed out malfunctioning autonomic nervous system in fibromyalgia (FM) patients. This is a common pathogenesis shared also by patients with nondipping blood pressure (BP) pattern. Therefore, we aimed to investigate the frequency of nondipping BP pattern in normotensive women with newly diagnosed FM compared with healthy women.

Sixty-seven normotensive women with new diagnosis of FM and 38 age-matched healthy volunteer women were recruited into the study. All subjects underwent 24-hour ambulatory BP monitoring on a usual working day. Individuals were defined as "dippers" if their nocturnal BP values decreased by more than 10% compared with daytime values; defined as "nondippers" in case of a decline less than 10%. Serum creatinine, fasting blood glucose, cholesterol levels, albumin, and thyroid-stimulating hormone levels were assessed.

Ambulatory measurements showed significantly higher diastolic BP values in patients with FM for both average of 24-hour recordings. Patients with FM had significantly lower systolic (9.1 ± 3.9 vs 11.5 ± 4.9, P = 0.010) and diastolic dipping ratios (12.3 ± 6.1 vs 16.1 ± 6.4, P = 0.004). The number of nondippers in the FM group was significantly higher than that of controls for both systolic (66% vs 34%, P = 0.002) and diastolic BP measurements (42% vs 21%, P=0.031). Patients with FM were 3.68 times more likely to be systolic nondipper and 2.69 times more likely to be diastolic nondipper.

We have demonstrated a significant relationship between FM and nondipping BP pattern, and we suggest that nondipping profile, which has been closely associated with cardiovascular morbidity, may appear as an additional risk factor in patients with FM.