Fibromyalgia and Nondipper Circadian Blood Pressure Variability

Salih İnal, MD; Esra Erkol İnal, MD; Gülay Ulusal Okyay, MD; Gökhan Tuna Öztürk, MD; Kürşad Öneç, MD; Galip Güz, MD

Disclosures

J Clin Rheumatol. 2014;20(8):422-426. 

In This Article

Abstract and Introduction

Abstract

Background and Objectives 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.

Methods 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.

Results 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.

Conclusions 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.

Introduction

Fibromyalgia (FM) is a noninflammatory rheumatologic disorder characterized mainly by musculoskeletal pain as well as fatigue, depression, cognitive dysfunctions, and sleep disturbances.[1] It affects approximately 2% of the general population and is 7 times more likely to occur in women rather than men.[2]

The pathophysiology involves a number of factors including genetic background, environmental stressors such as psychosocial factors, and abnormalities in neuroendocrine system functions.[3] Studies manifesting decreased nociceptive reflex thresholds and dispersed nature of the pain perception suggested a central nervous system abnormality for patients with FM.[4,5] Noteworthy, a number of studies indicating aberrant circadian rhythm with persistent nocturnal sympathetic hyperactivity,[6] diminished heart rate variability,[7] decreased microcirculatory vasoconstriction, and orthostatic hypotension[3] have pointed out particularly malfunctioning autonomic nervous system. The distortion of biological rhythms might have contributed to the major complaints of patients such as fatigue and sleep disturbances.[8]

Normally, blood pressure (BP) rhythm is under tight control of the autonomic nervous system. During the circadian rhythm, BP values generally decline at night hours by more than 10% compared with that of daytime values, which is referred to as a "dipping pattern." The absence of this anticipated decline in nocturnal values is defined as "nondipping pattern" and has been closely associated with target organ damage in either hypertensive or normotensive subjects.[9,10] Trials showing nocturnal decrease in parasympathetic system activity and nocturnal increase in sympathetic system activity support that nondippers have also autonomic nervous system abnormalities.[11,12]

The common etiopathogenetic points between FM and nondipper BP pattern are striking. Nevertheless, in today's knowledge, there is lack of data regarding this issue. In the presented study, we aimed to investigate the frequency of nondipping BP pattern (decline of nocturnal BP values <10% compared with daytime values) in normotensive women with newly diagnosed FM compared with healthy women.

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