Figures
- FIGURE 1
COPDGene consort diagram.
- FIGURE 2
Income status by Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage. Higher- and low-income status was identified for phase 2 subjects who reported annual income based on income >USD 15 000 (higher) and <USD 15 000 (low). Percentage of subjects in higher- and low-income categories is shown for each GOLD stage. In general, the distribution of income status is similar across the GOLD stages except for an excess of low-income subjects in the preserved ratio impaired spirometry group and fewer in GOLD stage 1.
Tables
- TABLE 1
Demographics and baseline disease severity
Low-income smokers (<USD 15 000 per year) Higher-income smokers (>USD 15 000 per year) p-value Subjects n 1549 3277 Age years 55.7±7.4 61.7±8.5) <0.0001 African American 57 16 <0.0001 Male 49 52 0.031 BMI kg·m−2 29.1±6.7 29.1±5.7 0.95 More than high-school education 45 77 <0.0001 ATS pack-years 42.5±25.0 42.2±22.6 0.66 Age started smoking years 16.7±5.1 17.2±4.1 0.0016 Current smoking status 73 36 <0.0001 Using respiratory medications 42 31 <0.0001 FEV1 % pred 78.4±23.2 80.4±23.0 0.0042 FVC % pred 87.7±17.8 89.6±16.5 0.0002 FEV1/FVC 0.70±0.14 0.68±0.14 0.0003 Percentage emphysema LAA@-950 HU 4.68±7.6 6.24±8.9 <0.0001 Percentage gas trapping LAA@-856 HU 19.3±17.9 20.5±17.8 0.0652 Airway wall thickness mm 1.063±0.231 1.018±0.211 <0.0001 Data are presented as mean±sd or %, unless otherwise stated. BMI: body mass index; ATS: American Thoracic Society; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; LAA: low-attenuation areas.
- TABLE 2
Symptoms, function and quality of life
Low-income smokers (<USD 15 000 per year) Higher-income smokers (>USD 15 000 per year) p-value Phase 1 Chronic bronchitis 22 14 <0.0001 mMRC score 1.58±1.46 0.93±1.24 <0.0001 mMRC score >2 49 28 <0.0001 Severe exacerbation within the past year 13 7 <0.0001 SGRQ total 31.74±23.3 19.3±18.8 <0.0001 6MWD feet 1297±381 1486±352 <0.0001 SF-36 PCS 42.0±11.2 47.1±10.0 <0.0001 SF-36 MCS 45.95±12.6 52.4±9.8 <0.0001 Phase 2 Chronic bronchitis 20 13 <0.0001 mMRC 1.64±1.51 0.99±1.29 <0.0001 mMRC score >2 52 31 <0.0001 Severe exacerbation within the past year 14 7 <0.0001 SGRQ total 31.79±23.1 19.6±19.0 <0.0001 6MWD feet 1168±438 1356±420 <0.0001 SF-36 PCS 39.9±11.4 45.3±10.6 <0.0001 SF-36 MCS 48.0±11.7 53.6±9.5 <0.0001 CAT score 15.0±9.2 10.5±7.7 <0.0001 Data are presented as % or mean±sd, unless otherwise stated. mMRC: modified Medical Research Council; SGRQ: St George's Respiratory Questionnaire; 6MWD: 6-min walking distance; SF-36: Medical Outcomes Study 36-item short-form questionnaire; PCS: physical component summary; MCS: mental component summary; CAT: Chronic Obstructive Pulmonary Disease Assesment Test.
- TABLE 3
Socioeconomic factors beyond income
Low-income smokers (<USD 15 000 per year) Higher-income smokers (>USD 15 000 per year) p-value Education beyond high school 45 77 <0.0001 Residence Own home 19 70 <0.0001 Rent 59 22 <0.0001 Lack a permanent home 5 0.5 <0.0001 Have health insurance 90 97 <0.0001 Access to preventative care Get preventative care from doctor/clinic 88 97 <0.0001 Get preventative care from emergency room 8 1 <0.0001 Do not get preventative care 4 2 <0.0001 Lack a primary-care physician 9 3 <0.0001 Have access to internet 55 89 <0.0001 Exposures Worked in a dusty job 54 40 <0.0001 Worked in a fumes-related job 49 45 <0.0001 Data are presented as %, unless otherwise stated.
- TABLE 4
Accommodation to healthcare costs
Low-income smokers (<USD 15 000 per year) Higher-income smokers (>USD 15 000 per year) p-value In the last year, because of the expense or lack of coverage, have you … Not gone to your doctor when you needed to 11 5 <0.0001 Not filled a prescription 10 6 <0.0001 Stretched out a prescription medication by taking less of it or less often than it was prescribed 9 7 0.005 Not gone to the hospital when you needed to 6 1 <0.0001 Gone to an emergency room to be treated 9 2 <0.0001 One or more of the above 25 14 <0.0001 Data are presented as %, unless otherwise stated.
- TABLE 5
Adjusted relationships of income to baseline computed tomography measures
Coefficient (95% CI) p>|t| Baseline emphysema Model R2 0.3287 Baseline FEV1 −5.91 (−6.24– −5.58) <0.0001 Height 0.15 (0.11–0.18) <0.0001 Current smoking −2.95 (−3.47– −2.44) <0.0001 Female −4.16 (−4.80– −3.53) <0.0001 Age at recruitment −0.075 (−0.11– −0.042) <0.0001 Education beyond high school −0.91 (−1.42– −0.40) <0.0001 Lower income −0.82 (−1.37– −0.27) 0.004 African American −2.21 (−2.81– −1.61) <0.0001 Smoking pack-years 0.012 (0.0023–0.022) 0.015 Baseline gas trapping Model R2 0.4874 Baseline FEV1 −14.67 (−15.30– −14.03) <0.0001 Height 0.39 (0.33–0.46) <0.0001 Current smoking −3.92 (−4.93– −2.92) <0.0001 Female −9.78 (−11.02– −8.54) <0.0001 Age at recruitment 0.74 (0.011–0.14) 0.022 Education beyond high school −1.38 (−2.36– −0.37) 0.007 Lower income 1.00 (−0.089–2.10) 0.072 African American −5.19 (−6.40– −3.99) <0.0001 Smoking pack-years 0.023 (0.0031–0.042) 0.023 Baseline airway wall thickness Model R2 0.2928 Baseline FEV1 −0.10 (−0.11– −0.095) <0.0001 Height 0.0036 (0.0027–0.0045) <0.0001 Current smoking 0.080 (0.066– 0.094) <0.0001 Female −0.18 (−0.20– −0.17) <0.0001 Age at recruitment −0.0020 (−0.0028– −0.0011) <0.0001 Education beyond high school −0.018 (−0.032– −0.0048) 0.008 Lower income 0.021 (0.0062– 0.036) 0.005 African American −0.07 (−0.083– −0.051) <0.0001 Smoking pack-years 0.00069 (0.00042–0.00095) <0.0001 FEV1: forced expiratory volume in 1 s.
- TABLE 6
Income status and 5-year change in spirometry, dyspnoea, health-related quality of life and imaging characteristics
Low-income smokers (<USD 15 000 per year) Higher-income smokers (>USD 15 000 per year) p-value FEV1 % pred −3.26±12.9 −1.40±10.1 <0.0001 FEV1 mL −225.6±342 −202.1±280 0.0115 FEV1 mL per year −40.0±61.5 −35.9±50.0 0.0142 Loss of >300 mL in FEV1 n (%) 570 (36.8%) 1055 (32.19%) 0.002 mMRC dyspnoea score# 0.0575±1.43 0.0649±1.14 0.87 SGRQ total score 0.0442±19.5 0.298±13.2 0.6 Distance walked feet¶ −130±401 −128±335 0.82 Adjusted lung density+ −1.90±12.1 −0.35±11.5 0.0003 Emphysema+ % 0.677±3.74 0.06±3.95 <0.0001 Gas trapping§ % 2.31±9.52 0.623±8.17 <0.0001 Airway wall thickness mm −0.0061±0.137 −0.0025±0.108 0.409 Current smokers −0.0051 −0.017 0.083 Former smokers −0.0086 0.0051 0.0291 Data are presented as mean±sd, unless otherwise stated. FEV1: forced expiratory volume in 1 s; mMRC: modified Medical Research Council; SGRQ: St George's Respiratory Questionnaire. #: n=1547 (low income), n=3271 (higher income); ¶: n=1503 (low income), n=3234 (higher income); +: n=1085 (low income), n=2489 (higher income); §: n=828 (low income), n=2133 (higher income).
- TABLE 7
Associations of income and education to disease progression
Coefficient (95% CI) p-value Change in FEV1 mL Model R2 0.0660 Baseline FEV1 % pred −2.78 (−3.13– −2.41) <0.0001 Current smoking −51.36 (−70.99– −31.73) <0.0001 Female 68.47 (51.85–85.09) <0.0001 Age at recruitment −0.39 (−1.54–0.77) 0.51 Education beyond high school −7.96 (−27.00–11.08) 0.41 Low income −36.58 (−57.23– −15.93) 0.001 African American race 49.21 (27.48–70.93) <0.0001 Smoking pack-years −0.89 (−1.27– −0.51) <0.0001 Change in emphysema Model R2 0.0925 Baseline emphysema −0.017 (−0.035–0.00073) 0.060 Baseline FEV1 % pred −0.051 (−0.058– −0.045) <0.0001 Current smoking 0.68 (0.39–0.98) <0.0001 Female −0.039 (−0.29–0.21) 0.76 Age at recruitment −0.0057 (−0.023–0.011) 0.51 Education beyond high school 0.21 (−0.075–0.49) 0.15 Low income 0.14 (−0.17–0.45) 0.39 African American race 0.31 (−0.019–0.64) 0.065 Smoking pack-years 0.0051 (−0.00070–0.011) 0.085 Change in airway wall thickness Model R2 0.1121 Baseline airway wall thickness −0.20 (−0.22– −0.18) <0.0001 Baseline FEV1 % pred −0.00018 (−0.00036– −0.0000048) 0.044 Current smoking 0.0060 (−0.0029–0.015) 0.185 Female −0.022 (−0.030– −0.014) <0.0001 Age at recruitment 0.00070 (0.00019–0.0012) 0.008 Education beyond high school −0.0013 (−0.0099–0.0073) 0.76 Low income 0.013 (0.0036–0.022) 0.007 African American race −0.015 (−0.025– −0.0050) 0.003 Smoking pack-years 0.00013 (−0.000042–0.00031) 0.136 FEV1: forced expiratory volume in 1 s.
Supplementary Material
Please note: supplementary material is not edited by the Editorial Office, and is uploaded as it has been supplied by the author.
Supplementary tables and figure 00069-2018_Supplement
