Beyond fatigue: Assessing variables associated with sleep problems and use of sleep medications in multiple sclerosis

Figures & data

Table 1 Study participant characteristics (N = 473)

	Mean ± SD n (%)
Sleep problems (MOSS Sleep Problems Index II)	35.9 ± 20.2
Sleep disturbance (MOSS Sleep Disturbance Subscale)	32.6 ± 25.9
Age (years)	52.3 ± 10.9
Female	391 (82.7)
Duration of MS (years)	14.5 ± 9.9
EDSS category
Mild (≤4.0)	145 (30.7)
Moderate (4.5–6.5)	240 (50.9)
Severe (≥7.0)	87 (18.4)
Education level
≤High school/GED	68 (14.4)
Technical/some college	180 (38.1)
Bachelors degree	140 (29.6)
Graduate degree	85 (18.0)
Married	323 (68.3)
Depression (PHQ-9)	6.5 ± 5.25
Fatigue (MFIS)	38.8 ± 17.9
Pain	4.7 ± 3.3
Nocturia	170 (36.0)
Restless leg-like symptoms	240 (50.7)
Leg cramps	165 (35.4)
Bed mobility problems	127 (27.1)

Abbreviations: EDSS, Expanded Disability Status Scale; GED, General Education Development test; MFIS, Modified Fatigue Impact Scale; MOSS, Medical Outcomes Study Sleep; MS, multiple sclerosis; PHQ-9, Patient Health Questionnaire; SD, standard deviation.

Table 2 Sleep aid medication use

	n (%)	Sleep problems	Sleep disturbance
Prescription medications
Never use	331 (70.0)	32.4 ± 19.3a	27.9 ± 24.4a
<1/week	17 (3.6)	40.8 ± 18.4	39.3 ± 23.1
1–2 times/week	16 (3.4)	52.7 ± 16.3	56.5 ± 24.4
3–4 times/week	17 (3.6)	54.0 ± 20.2	56.0 ± 28.5
Every day	92 (19.5)	41.3 ± 19.7	39.9 ± 25.4
Over-the-counter medications
Never use	369 (78.0)	34.0 ± 19.7b	29.3 ± 24.7c
<1/week	28 (5.9)	31.9 ± 19.2	29.6 ± 21.6
1–2 times/week	17 (3.6)	52.1 ± 20.8	55.2 ± 27.4
3–4 times/week	22 (4.7)	43.1 ± 16.2	46.5 ± 23.7
Every day	37 (7.8)	45.5 ± 21.4	48.6 ± 28.4

Notes: Sleep problems were measured using the MOSS Sleep Problems Index II subscale and sleep disturbance using the MOSS sleep disturbance subscale. Sometimes users were defined as those in the middle three categories (<1/week to 3–4 times/week). Wilcoxon rank sum tests were used for statistical comparisons and P-values <0.004 were considered significant due to Bonferroni adjustment for multiple tests.

a Score is statistically significantly different compared to both sometimes users and every day users (all P < 0.0001).

b Score is statistically significantly different compared to every day users (P = 0.002).

c Score is statistically significantly different compared to sometimes (P = 0.002) and every day users (P < 0.0001).

Table 3 Multiple linear regression results examining statistically significant factors associated with sleep problems in MS (N = 465)

		Final model adjustedR^2				0.45
Model predictor	Coefficient	Standard error	Standardized beta coefficient	t-score	P-value	R^2contribution
Depression	1.47	0.23	0.33	6.51	<0.001	0.329
Leg cramps	3.44	0.80	0.18	4.30	<0.001	0.039
Age	−0.28	0.07	−0.15	−3.80	<0.001	0.030
Pain	0.96	0.27	0.16	3.63	<0.001	0.029
Female sex	4.44	1.69	0.08	2.63	0.009	0.005
Fatigue	0.15	0.06	0.13	2.41	0.016	0.008
Duration of MS	−0.19	0.09	−0.1	−2.29	0.023	0.005
Nocturia	3.61	1.61	0.09	2.24	0.025	0.004

Notes: The sleep problems outcome was defined using the Sleep Problems Index II subscale of the MOSS Scale.

Abbreviations: MOSS, Medical Outcomes Study Sleep; MS, multiple sclerosis.