Table 2.

Study Quality Assessment Using the Newcastle-Ottawa Quality Assessment Scale

Study and year	Selection	Comparability	Outcome	NOS score	Limitations; items missing from NOS
Case–control studies
Dublin et al., 2011	****	**	***	9/9	Older adult population ≥ 65
Velly et al., 2017	***	**	***	8/9	CAP requiring hospitalization; selection: hospital controls
Wiese et al., 2018	***	**	***	8/9	Outcome was invasive pneumococcal disease, 74% with pneumonia; selection: hospital controls
Edelman et al., 2019	***	**	***	8/9	59% of patients were HIV positive; selection: hospital controls
Hamina, et al. 2019	****	**	***	9/9	Patients with Alzheimer’s disease
Cohort studies
Vozoris et al., 2016	***	**	***	8/9	All patients had COPD and outcome was hospitalization with pneumonia or COPD; selection: representativeness
Kim et al., 2019	***	**	***	8/9	All patients underwent total knee replacement; selection: representativeness
Shah et al., 2019	***	**	***	8/9	All patients underwent craniotomy; selection: representativeness

Asterisk indicated item achieves one point on the NOS

NOS Newcastle Ottawa Scale, HIV human immunodeficiency virus, COPD chronic obstructive pulmonary disease