Poor sleep in scleroderma linked to inadequate sleep hygiene: Study
Acid reflux, depression symptoms also contributed to poor experience
People with systemic sclerosis (SSc) face significantly worse sleep quality than those with rheumatoid arthritis (RA) and healthy people, a study reports.
Poor sleep hygiene and clinical factors, including gastroesophageal reflux disease, that is, acid reflux, and depression-like symptoms, were key contributors.
These findings highlight how “enhancing sleep hygiene practices may serve as a crucial strategy to improve the overall sleep quality in SSc,” the researchers wrote. The study, “Inadequate sleep hygiene as a key factor in poor sleep quality in systemic sclerosis: an observational, cross-sectional study,” was published in Rheumatology International.
In SSc, also called scleroderma, scar tissue accumulates in the skin and also can in internal organs, including the heart, kidneys, lungs, and digestive tract. Sleep impairments are known to be high among people with SSc and RA, also an autoimmune disorder.
Here, researchers in Turkey evaluated how sleep hygiene — the collection of lifestyle, environmental, and behavioral strategies for healthy sleep habits — influences sleep quality and correlates with clinical parameters in SSc patients. They also compared sleep hygiene and sleep quality between people with SSc, those with RA, and healthy people, who served as controls. Each group was composed of 70 age-matched participants, all female. The median age in the SSc group was 52.7.
Analyzing sleep in SSc
SSc patients have significantly worse sleep quality than those with RA and healthy controls, as evidenced by higher total scores in the Pittsburgh Sleep Quality Index (PSQI), an analysis showed. SSc patients scored higher, that is, worse, on several subscales of the PSQI, including sleep quality, the time it takes to fall asleep, or sleep latency, sleep efficiency, and sleep disturbances.
Moreover, Sleep Hygiene Index (SHI) scores were also significantly worse in SSc patients than RA patients and healthy controls, suggesting poorer sleep habits. No significant difference was observed between RA patients and healthy people.
The prevalence of poor sleepers — defined as those with total PSQI scores of 6 or higher — was significantly more common among SSc patients than in the RA and control groups.
In a statistical analysis, SSc patients were 4.5 times more likely to have poor sleep over RA patients and healthy controls. After adjusting for multiple factors, including age and smoking status, SSc patients still showed a 4.61 times higher risk of poor sleep. Also, for each increase of one unit in the SHI score, the odds of poor sleep quality increased by 1.15 times with SSc.
SSc patients with gastroesophageal reflux disease had a 6.82 times higher likelihood of poor sleep. Associations between worse scores in the Beck Depression Inventory and poor sleep were also found. Contrary to the scientists’ expectations, good sleepers had higher body mass index, which is a measure of body fat, and longer disease duration than poor sleepers.
A measure called receiver operating function (ROC) analysis revealed that a cutoff of 10.5 in the SHI score defined poor sleep in SSc patients with 80% sensitivity and 50% specificity. The same analysis failed to establish a cutoff for RA patients. ROC values range from 0.5 to 1, wherein higher scores reflect a better ability to accurately differentiate between two groups. A test’s sensitivity is its ability to correctly identify those with a given disease, while specificity refers to correctly identifying those without it.
A review of clinical parameters showed that most SSc patients (88.6%) engaged in moderate exercise. Almost two-thirds (64.3%) had interstitial lung disease, and 20% had pulmonary hypertension. Interstitial lung disease is marked by lung inflammation and scarring, and is the leading cause of death in SSc.
Poor sleepers also exhibited higher pain scores and increased rates of depression and anxiety.
“SSc patients tend to have lower sleep hygiene and worse sleep quality,” the researchers wrote. “Sleep hygiene strategies that include many steps to increase sleep hygiene can ameliorate sleep disturbance in these patients.”
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