Table 1.
Baseline characteristics of study population
| Before matching | After matching | |||
|---|---|---|---|---|
| RLS negative (n=3,515,660) |
RLS positive (incident) (n=4,113) |
RLS negative (n=3,696) |
RLS positive (incident) (n=3,696) |
|
| Age (years) | 60±14 | 59±11 | 59±13 | 59±11 |
| Gender (male) | 3,264,846 (93) | 3,816 (93) | 3,439 (93) | 3,446 (93) |
| Outcomes: | ||||
| Death | 726,539 (21) | 956 (23) | 782 (21) | 853 (23) |
| Incident CHD event* | 89,274 (3) | 456 (12) | 157 (4) | 425 (12) |
| Incident stroke event** | 61,811 (2) | 314 (8) | 104 (3) | 293 (8) |
| New CKD | 353,470 (10) | 886 (22) | 503 (14) | 787 (21) |
| Race: | ||||
| White | 2,471,180 (79) | 3,681 (91) | 3,222 (87) | 3,372 (91) |
| African-American | 543,365 (17) | 248 (6) | 399 (11) | 221 (6) |
| Hispanic | 72,386 (2) | 33 (1) | 35 (1) | 30 (1) |
| Other Race | 67,727 (2) | 80 (2) | 40 (1) | 73 (2) |
| Marital status: | ||||
| Married | 1,866,693 (56) | 2,090 (53) | 1,947 (53) | 1,946 (53) |
| Single | 375,896 (11) | 312 (8) | 401 (11) | 293 (8) |
| Divorced | 856,487 (26) | 1,242 (32) | 1,058 (29) | 1,195 (32) |
| Widow | 247,601 (7) | 283 (7) | 290 (8) | 262 (7) |
| Other sociodemographic: | ||||
| Mean per capita income (USD) | 22,955 (11,696–36,167) | 20,846 (12,029–31,300) | 20,473 (11,180–31,427) | 20,917 (12,091–31,315) |
| Baseline eGFR (ml/min./1.73m2) | 84±15 | 84±15 | 84±15 | 84±15 |
| BMI (kg/m2) | 28.8±5.2 | 29.7±5.5 | 29.6±5.6 | 29.7±5.5 |
| Comorbidities: | ||||
| Hypertension | 2,062,000 (59) | 2,642 (64) | 2,363 (64) | 2,367 (64) |
| Diabetes mellitus | 824,164 (23) | 1,278 (31) | 1,150 (31) | 1,134 (31) |
| Cardiovascular Disease*** | 396,243 (11) | 670 (16) | 574 (15) | 613 (17) |
| Congestive Heart Failure | 154,007 (4) | 300 (7) | 281 (8) | 273 (7) |
| Cerebrovascular Disease | 211,618 (6) | 327 (8) | 295 (8) | 301 (8) |
| Peripheral Arterial Disease | 189,796 (5) | 391 (10) | 368 (10) | 355 (10) |
| Chronic Lung Disease | 632,228 (18) | 1,295 (31) | 1,172 (32) | 1,160 (31) |
| Dementia | 29,443 (0.8) | 29 (0.7) | 38 (1) | 24 (1) |
| Rheumatologic Disease | 48,438 (1) | 76 (2) | 86 (2) | 68 (2) |
| Peptic ulcer disease | 64,471 (2) | 131 (3) | 77 (2) | 117 (3) |
| Liver Disease | 41,651 (1) | 74 (2) | 53 (1) | 71 (2) |
| All malignancies | 359,970 (10) | 413 (10) | 377 (10) | 377 (10) |
| AIDS/HIV | 21,466 (0.6) | 17 (0.4) | 12 (0.3) | 15 (0.4) |
| Depression | 316,188 (9) | 811 (20) | 735 (20) | 720 (19) |
| Obstructive Sleep Apnea | 432,871 (12) | 1693 (41) | 1536 (42) | 1503 (41) |
| Periodic Limb Movement in Sleep | 6352 (0.2) | 108 (3) | 82 (2) | 101 (3) |
Dichotomous/dummy variables are presented as number of patients and percentage; continous variables are presented as mean±SD or median (interquartile range, IQR)
in cardiovascular disease (see below) free patients at baseline
in stroke disease free patients at baseline
Cardiovascular Disease was defined as acute myocardial infraction, angina, coronary artery disease, previous coronary artery bypass grafting or percutaneous coronary intervention
Abbreviations: AIDS: Acquired immundeficiency syndrome; BMI: Body mass index; CHD: coronary heart disease; CKD: Chronic Kidney Disease; eGFR: Estimated glomerular filtration rate; HIV: Human Immundeficiency Virus; IQR: Interquartile range; RLS: Restless Legs Syndrome; SD: Standard deviation; USD: US dollars