Evaluation of the reliability and validity of the medical outcomes study sleep
scale in patients with painful diabetic peripheral neuropathy during an
international clinical trial.

Muriel Viala-Danten, Susan Martin, Isabelle Guillemin and Ron D Hays.

Health and Quality of Life Outcomes 2008, 6:113.

Background

Sleep is an important element of functioning and well-being. The Medical
Outcomes Study Sleep Scale (MOS-Sleep) includes 12 items assessing sleep
disturbance, sleep adequacy, somnolence, quantity of sleep, snoring, and
awakening short of breath or with a headache. A sleep problems index, grouping
items from each of the former domains, is also available. This study evaluates
the psychometric properties of MOS-Sleep Scale in a painful diabetic peripheral
neuropathic population based on a clinical trial conducted in six countries.

Methods

Clinical data and health-related quality of life data were collected at baseline
and after 12 weeks of follow-up. Overall, 396 patients were included in the
analysis. Psychometric properties of the MOS-Sleep were assessed in the overall
population and per country when the sample size was sufficient. Internal
consistency reliability was assessed by Cronbach's alpha; the structure of the
instrument was assessed by verifying item convergent and discriminant criteria;
construct validity was evaluated by examining the relationships between MOS-
Sleep scores and sleep interference and pain scores, and SF-36 scores; effect-
sizes were used to assess the MOS-Sleep responsiveness. The study was conducted
in compliance with United States Food and Drug Administration regulations for
informed consent and protection of patient rights.

Results

Cronbach's alpha ranged from 0.71 to 0.81 for the multi-item dimensions and the
sleep problems index. Item convergent and discriminant criteria were satisfied
with item-scale correlations for hypothesized dimensions higher than 0.40 and
tending to exceed the correlations of items with other dimensions, respectively.
Taken individually, German, Polish and English language versions had good
internal consistency reliability and dimension structure. Construct validity was
supported with lower sleep adequacy score and greater sleep problems index
scores associated with measures of sleep interference and pain scores. In
addition, correlations between the SF-36 scores and the MOS-Sleep scores were
low to moderate, ranging from -0.28 to -0.53. Responsiveness was supported by
effect sizes > 0.80 for patients who improved according to the mean sleep
interference and pain scores and clinician and patient global impression of
change (p < 0.0001).

Conclusions

The MOS-Sleep had good psychometric properties in this painful diabetic
peripheral neuropathic population. Trial registration: As this study was
conducted from 2000 to 2002 (i.e., before the filing requirement came out), no
trial registration number is available.

8/17/2004

Hays, Ron D., Martin, Susan A., Sesti, Anne M., & Spritzer, Karen L. (2005).
Psychometric properties of the Medical Outcomes Study sleep measure.
Sleep Medicine, 6(1), 41-44.

Background and purpose: Sleep is an active and highly organized biological
process that is an important component of life. Self-report measures of sleep
provide information that can be useful for characterizing the quality of sleep
in subgroups of the population. A 12-item self-report sleep measure, the Medical
Outcomes Study (MOS) Sleep measure, was developed and evaluated previously in a
sample of 3445 individuals with chronic illness.

Patients and methods: In this study, we evaluate the psychometric properties of
the MOS Sleep measure in a nationally representative sample of 1011 US adults
aged 18 and older and in a sample of 173 adults with neuropathic pain
participating in a clinical drug trial.

Results: The average age of the general population sample was 46; 51% were
female and 81% were white. The average age of the sample of adults with
neuropathic pain was 72; 53% were female and 95% were white. Internal
consistency reliability estimates for the MOS Sleep scales were 0.73 or higher,
with the exception of the daytime somnolence scale in the US general population,
which was 0.63. At baseline of the clinical trial, the neuropathic pain patients
reported significantly more sleep disturbance and daytime somnolence, as well as
less quantity and adequacy of sleep than patients in the general US population.
The MOS Sleep scales were found to be responsive to change in the clinical trial
with statistically significant improvements observed after administration of
pregabalin for sleep disturbance (standardized response mean, SRM=-0.76,
P=0.0007), shortness of breath (SRM=-0.20, P=0.0302), sleep adequacy (SRM=0.57,
P=0.0014), sleep quantity (SRM=0.55, P=0.0086), and sleep problems (SRM=-0.62,
P=0.0036).

Conclusions. This study provides further support for the reliability and
validity of the MOS Sleep measure. The instrument can be used to assess
important aspects of sleep perceived by adults in the general population or
participating in clinical studies.

Keywords: MOS sleep measure; Self-reports; Reliability; Validity; Patient
reported outcomes