Table 1.

Characteristics of included studies

Author (year)	Geographical setting(s)	Design	Data source(s)	Type of data	Study period	Patient population
Ali et al. (2019) [17]	UK	Retrospective, observational cohort study	Royal Stoke University Hospital	Paper notes and electronic clinical records	2017–9	11 patients with SMA type I (45% male; median age: 2 years) treated with nusinersen
Armstrong et al. (2016) [19]	USA	Retrospective, observational cohort study	Military Health System Data Repository (MDR)	Defense Health Agency corporate healthcare data	2003–12	239 patients with SMA (45% male; mean age NR) [phenotype NR]
Chambers et al. (2020) [25]	Australia	Cross-sectional, observational study; and retrospective, observational cohort study	Survey administrated to caregivers via two neuromuscular clinics and a patient support organization; the Sydney Children’s Hospital SMA clinic; and local unit costs	Self-reported data; and health service use and insurance data	2016–17	40 patients with SMA (48% male; mean age: 9 years) [10% with SMA type I, 65% with SMA type II, and 25% with SMA type III]
Cardenas et al. (2019) [16]	USA	Retrospective, observational cohort study	Kids’ Inpatient Database (KID) part of the HCUP	Claims data	2012	237 patients with SMA type I (43% male; mean age NR)
Darbà ‍et al. (2019) [15]	Spain	Retrospective, observational cohort study	Spanish claims database Minimum Basic Data Set (Conjunto Mínimo Básico de Datos [CMBD])	Claims data	1997–2015	705 patients with SMA type I, SMA type III, progressive SMA, other SMA, or unspecified SMA (62% male; mean age: 37 years) [distribution of phenotypes NR]
Darbà (2020) [24]	Spain	Retrospective, observational cohort study	Public Data Analysis for Health Research and Innovation Program (PADRIS) database	Electronic clinical records	2014–17	396 patients with SMA (53% male; mean age: 57 years) (6% with SMA type I, 29% with SMA type III, 43% with progressive SMA, 10% with other SMA, and 13% with unspecified SMA)
Droege et al. (2019) [18]	USA	Retrospective, observational cohort study	Symphony Health’s Integrated Dataverse (IDV)	Claims data	2016–18	349 patients with SMA type I (44% male; mean age: 9 years) receiving conventional therapy; 45 patients with SMA type I (38% male; mean age: 12 years) receiving nusinersen; 5728 patients with SMA types II–IV (52% male; mean age: 31 years) receiving conventional therapy; and 404 patients with SMA types II–IV (49% male; mean age: 15 years) receiving nusinersen
Klug et al. (2016) [20]	Germany	Cross-sectional, observational study	Survey administrated to patients identified via the German SMA patient registry; and local unit costs	Self-reported data	2013	189 patients with SMA (59% male; median age: 19 years) (6% with SMA type I, 39% with SMA type II, and 55% with SMA type III)
Lee et al. (2019) [14]	USA	Retrospective, observational cohort study	HCUP; and the Center for Health Information and Analysis	Claims data	2005–13	229 patients with severe SMA (distribution of sex and mean age NR) [phenotype NR]
López-Bastida et al. (2017) [13]	Spain	Cross-sectional, observational study	Survey administrated to patients via national patient associations; and local unit costs	Self-reported data	2015	81 patients with SMA (42% male; mean age: 7 years) [10% with SMA type I, 74% with SMA type II, and 16% with SMA type III]
Marcellusi et al. (2019) [22]	Italy	Cross-sectional, observational study	Survey administrated to patients via a national patient association; and local unit costs	Self-reported data	2018	118 patients with SMA (41% male; mean age: 18 years) (23% with SMA type I, 48% with SMA type II, and 29% with SMA type III)
Peña-Longobardo et al. (2020) [26]	France; Germany; and UK	Cross-sectional, observational study	Survey administrated to caregivers via a patient organization/registry; and local unit costs	Self-reported data	2015	27 French patients with SMA (41% male; mean age: 6 years) [19% with SMA type I, 48% with SMA type II, and 33% with SMA type III]; 25 German patients with SMA (28% male; mean age: 10 years) [44% with SMA type I, 48% with SMA type II, and 8% with SMA type III]; and 34 UK patients with SMA (50% male; mean age: 6 years) [21% with SMA type I, 59% with SMA type II, and 21% with SMA type III]
Tan et al. (2019) [21]	USA	Retrospective, observational cohort study	HealthCore Integrated Research Database	Claims data	2006–16	341 patients with SMA (55% male; mean age: 45 years) [7% with SMA type I, 6% with SMA type II/III, and 87% with SMA type IV]
Zuluaga‑Sanchez et al. (2019) [23]	Sweden	Modeling study (CEA)	Clinical expert input; and local unit costs	Clinical and economic model input data	2016	Patients with SMA type I (45% male; mean age: 6 months) and SMA types II–IV (47% male, mean age: 4 years) [number of patients NA]

CEA cost-effectiveness analysis, HCUP Healthcare Cost and Utilization Project, NA not applicable, NR not reported, SMA spinal muscular atrophy