TABLE 1.
Demographic and Clinical Characteristics of Periodic Leg Movement Index Category (PLMI <15 and PLMI ≥15)
| PLM Category† | |||
|---|---|---|---|
| PLMI <15 | PLMI ≥15 | ||
| Subjects/Observations (1084/2335) | 1572 observations (n=772) | 763 observations (n=312, 28.8%‡) | |
| Characteristic | n(%) or mean ± SE | n(%) or mean ± SE | p-value |
| Age (years) | 57.7 ± 0.3 | 60.7 ± 0.3 | p<0.0001 |
| Male | 795 (50.6%) | 466 (61.1%) | p=0.0003 |
| BMI (kg/m2) | 31.8 ± 0.2 | 31.7 ± 0.2 | p=0.40 |
| Cardiovascular disease | 118 (7.5%) | 95 (12.5%) | p=0.0058 |
| Coronary artery disease | 92 (5.9%) | 81 (10.6%) | p=0.0018 |
| Hypertension | 527 (33.5%) | 349 (45.7%) | p=0.0007 |
| Alcohol use (840/1784) | 4.6 ± 0.2 | 4.88 ± 0.24 | p=0.13 |
| Medication* | |||
| Exacerbates RLS Symptoms | 519 (33.1%) | 272 (36.0%) | p=0.0152 |
| Improves RLS Symptoms | 40 (2.6%) | 30 (4.0%) | p=0.33 |
| Depression (1075/2221) | 391 (25.9%) | 221 (31.1%) | p=0.0013 |
| Anxiety | 212 (13.5%) | 113 (14.8%) | p=0.77 |
| RLS Symptoms (881/1949)** | 499 (37.9%) | 330 (52.2%) | p<0.0001 |
| PLMI† | |||
| PLMI | 5.9 ± 0.2 | 33.8 ± 0.9 | p<0.0001 |
| Ln PLMI | 1.5 ± 0.0 | 3.3 ± 0.0 | p<0.0001 |
| Total Sleep Time | 370.4 ± 1.8 | 349.1 ± 2.7 | p<0.0001 |
| Sleep efficiency (%) | 81.1 ± 0.0 | 76.3 ± 0.0 | p<0.0001 |
| OSA | |||
| AHI adjusted (1037/2210)*** | 7.6 ± 0.3 | 7.5 ± 0.4 | p=0.91 |
| Ln AHI +1(1037/2210) | 1.6 ± 0.03 | 1.6 ± 0.04 | p=0.41 |
| AHI >15 | 278 (17.7%) | 158 (20.7%) | p=0.49 |
| Insomnia (at lab) | 754 (48.0%) | 410 (53.7%) | p=0.29 |
| Shift work | 83 (5.3%) | 37 (4.9%) | p=0.84 |
| Habitual sleep (mean) | 7.2 ± 0.0 | 7.3 ± 0.0 | p=0.45 |
| Habitual sleep (<6 hours) | 167 (10.6%) | 105 (13.8%) | p=0.31 |
Reported n (%) and mean ± standard error (SE) based on observations, not subjects. p-values based on F statistic or χ2 test for homogeneity.
†
PLMI Category based Stanford’s PLM detector,
‡
n based on first visit,
*
See Methods Section for more information about medication categorization,
**
Presence of RLS symptoms, as described in the Methods Section,
***
positive airway pressure users not counted in AHI as continuous variable. PLMI, periodic leg movement index; BMI, body mass index; RLS, restless legs syndrome symptoms; Ln, natural logarithm, OSA, obstructive sleep apnea; AHI, apnea hypopnea index.