Table 1

Baseline characteristics of systemic sclerosis hospitalizations with and with lung involvement

VariablesSSc (n=62,930)
Without lung (n=57,835)With lung (n=5095)P value
Mean age (y)62.9559.91<0.0001
Female (%)84.9779.96<0.0001
Race (%)<0.0001
 White68.3756.63
 Black15.1722.51
 Hispanic11.1013.16
 Asian1.803.08
 Native Americans0.830.82
 Others2.743.80
Charlson Comorbidity Index (%)0.4973
 0
 125.0225.02
 224.1225.71
 ≥350.8649.26
Hospital bed size (%)<0.0001
 Small16.9813.84
 Medium26.5221.10
 Large56.5165.06
Hospital teaching status (%)<0.0001
 Non-teaching26.9418.94
 Teaching74.0681.06
Hospital location (%)0.1798
 Rural6.745.59
 Urban93.2694.41
Expected primary payer (%)0.0125
 Medicare65.2660.28
 Medicaid9.7210.83
 Private23.4726.78
 Self-pay1.562.11
Median household income (quartile) (%)0.2261
 1st (0th–25th)25.7428.37
 2nd (26th–50th)25.1122.62
 3rd (51st–75th)25.0424.50
 4th (76th–100th)24.1124.50
Hospital region (%)0.0679
 Northeast20.3123.26
 Midwest23.9319.92
 South35.2636.51
 West20.5120.31
Dyslipidemia (%)30.6725.120.0005
Old MI (%)5.855.200.4234
Atrial fibrillation/flutter (%)13.3015.800.0293
COPD (%)18.9918.650.8090
Carotid artery disease (%)1.130.980.6578
Old stroke (%)6.624.810.0241
Hypertension (%)37.0529.15<0.0001
Peripheral vessel disease (%)5.383.040.0012
Hypothyroidism (%)25.0821.300.0090
DM type 1 and type 2 (%)15.9714.130.1399
Obesity (%)8.548.340.8297
CHF (%)24.7033.79<0.0001
CKD (%)21.9221.590.8167
Liver disease (%)7.956.180.0317
Maintenance hemodialysis (%)3.543.340.7336
Smoking (%)23.4427.380.0060
Anemia (%)41.1039.940.4861
  • Median household income refers to median household income for patient’s zip code.

  • CHF, congestive heart failure (chronic); CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; DM, diabetes mellitus; MI, myocardial infarction; SSc, systemic sclerosis.