Table 1

SCTC-DI final items—coefficient calculations and weighted score

	Item	Mortality coeff	Morbidity coeff	Combined coeff	Weighted score
	Musculoskeletal and skin
1	Joint contracture defined as any degree of contracture with the inability to reduce the joint to the anatomically neutral position in any small joint of the fingers.	−0.35	0.49	0.49	2
2	Joint contracture defined as any degree of contracture with the inability to reduce the joint to the anatomically neutral position in the large joints, specifically elbows and knees.	−0.35	0.49	0.49	2
3	Sicca symptoms defined as presence of patient-reported dry eyes and/or dry mouth requiring treatment on a daily basis, for example, lubricant eye-drops, punctual plugs, saliva replacement.	−0.10	0.75	0.75	3
4	Proximal muscle weakness on clinical examination defined as shoulder abduction and/or hip or knee flexion less than 5/5 power (not due to contracture or pain).	0.60	0.92	0.76	3
5	Calcinosis complicated by infection or requiring surgery.	−0.21	1.08	1.08	4
	Vascular
6	Digital ulceration defined as loss of epithelialisation, of any degree, of the epidermis, the dermis and/or the subcutaneous tissue, distal to or at the proximal interphalangeal joint of the hands or feet not thought to be due to trauma and refractory to therapy.	0.79	0.37	0.58	2
7	Digital amputation (surgical or autoamputation).	0.96	1.09	1.03	3
	Gastrointestinal
8	Oesophageal dysmotility defined as distal dysphagia refractory to treatment with differential diagnoses (eg, oesophageal stricture or malignancy) excluded by endoscopy.	−0.21	0.12	0.12	1
9	Pseudo-obstruction with symptoms such as vomiting or constipation, with dilatation of the small and/or large bowel on imaging.	0.93	−0.82	0.93	3
10	Low body mass index of <18.5 kg/m² or weight loss of >10% in the last 12 months.	0.68	0.74	0.71	2
11	Gastric antral vascular ectasia confirmed on endoscopy.	0.67	0.32	0.50	2
12	Oesophageal stricture confirmed on testing such as endoscopy or barium swallow.	0.15	0.20	0.18	1
13	Symptoms of gastro-oesophageal reflux disease (heart burn) refractory to treatment and confirmed on endoscopy.	0.03	0.71	0.37	1
	Respiratory
14	Moderate to severe interstitial lung disease with >20% extent on HRCT of the chest.	0.19	0.97	0.58	2
15	Moderate to severe interstitial lung disease with >20% extent on HRCT of the chest and forced vital capacity <70% on lung function tests.	1.11	2.47	1.79	6
16	Dependence on home oxygen.	0.88	1.99	1.44	5
	Cardiovascular
17	Pulmonary arterial hypertension (defined as mean pulmonary arterial pressure >25 mm Hg at rest and pulmonary arterial wedge pressure <15 mm Hg on right heart catheterisation).	0.75	0.59	0.67	2
18	Moderate to severe right ventricular dysfunction noted on echocardiography report based on assessment of any measure of RV function by experienced cardiologist.	1.81	2.49	2.15	7
19	Myocardial disease attributable to SSc based on a constellation of clinical features and supportive investigations, for example, syncope secondary to conduction abnormality, arrhythmia requiring defibrillator, heart block requiring permanent pacemaker or ablation, systolic or diastolic dysfunction on TTE.	0.85	0.77	0.81	3
20	Presence of moderate to large pericardial effusion equivalent to greater than 1 cm on TTE.	0.45	0.09	0.27	1
	Renal
21	History of scleroderma renal crisis (SRC), either hypertensive or normotensive, as defined by the International Scleroderma Renal Crisis Study Investigators.45	0.46	1.54	1.00	3
22	History of SRC or other SSc-related kidney disease and persistent renal impairment with estimated glomerular filtration rate <45 mL/min/1.73 m^2.	0.66	1.76	1.21	4
23	SRC with stage 5 renal impairment defined as need for renal replacement therapy.	1.08	2.16	1.62	5

Coeff, coefficient;HRCT, high-resolution CT;RV, right ventricular;SCTC-DI, Scleroderma Clinical Trials Consortium-Damage Index; SSc, systemic sclerosis; TTE, transthoracic echocardiogram.