Yarnall 2015.

Study characteristics
Methods	Design: retrospective case‐control Setting: community and outpatient Country: UK Duration of follow‐up: 1.5 years Covariates controlled for: age, gender, years of education, disease duration, MDS‐UPDRS III, levodopa equivalent daily dose and GDS‐15 (note: unclear what was controlled for in final model)
Participants	Participants numbers: 219 Population type: people with Parkinson's disease Sex: 40% women (88) Age (mean): 69 years
Prognostic factors	Anticholinergic burden measurement method: ADS scale
Outcomes	Outcomes assessed: MCI; cognitive decline Outcome ascertainment MCI: not clear Outcome ascertainment cognitive decline: MMSE, MoCA, in addition to tests of attention, visual memory, executive, language and visuospatial function Diagnostic criteria MCI: PD‐MCI was determined using the MDS criteria Diagnostic criteria cognitive decline: scores on cognitive testing
Source of funding	Parkinson's UK grant
Notes
Item	Authors' judgement	Support for judgement
Study participation	No	Parkinson's disease population.
Study attrition	Unclear	No comparison of completers vs non‐completers.
Prognostic factor measurement	Unclear	Not particularly clear how prognostic factor was measured but seems to be self‐report. Repeated measurements taken at baseline and 18 months.
Outcome measurement	Unclear	No blinding but ADS ratings likely assigned in retrospect.
Study confounding	Yes	Appropriate variables controlled for.
Reverse causation	No	ADS at baseline and at 18 months pooled so no restriction on ADS use before cog assessment at 18 months.
Statistical analysis and reporting	No	Uses backward stepwise regression to determine model covariates for use in exploring ADS association with various measures of cognition. Not stated what variables were controlled for in the final model.

ACB: Anticholinergic Cognitive Burden; ACT: Adult Changes in Thought; ADS: Anticholinergic Drug Scale; AGECAT: Automated Geriatric Examination for Computer Assisted Taxonomy; ANDI: Alzheimer's Disease Neuroimaging Initiative; ApoE: apolipoprotein E; ARS: Anticholinergic Risk Scale; BMI: body mass index; CAD: coronary artery disease; CES‐D: Center for Epidemiologic Studies Depression Scale; CHF: congestive heart failure; COPD: chronic obstructive pulmonary disease; CNAM‐TS: Caisse Nationale d'Assurance Maladie des Travailleurs Salariés; CRF: cardiovascular risk factor; DBI‐ach: anticholinergic component of the Drug Burden Index; DSM‐III: Diagnostic and Statistical Manual of Mental Disorders Third Edition; DSM‐III‐R: Diagnostic and Statistical Manual of Mental Disorders Third Edition Revised; DMS‐IV: Diagnostic and Statistical Manual of Mental Disorders Fourth Edition; DSM‐5: Diagnostic and Statistical Manual of Mental Disorders Fifth Edition; ED: emergency department; GDS: Geriatric Depression Screen; GP: general practitioner; HVRT: Hopkins Verbal Recall Test; IADL: instrumental activity of daily living; ICD‐9‐CM: International Classification of Diseases, Ninth Revision, Clinical Modification; ICD‐10: International Classification of Diseases, Tenth Revision; MCI: mild cognitive impairment; MDS‐UPDRS III: Motor Rating Scale – Unified Parkinson's Disease Rating Scale III; MMSE: Mini‐Mental State Examination; MoCA: Montreal Cognitive Assessment; NIH: National Institutes of Health; NINCDS‐ADRDA: Association Internationale pour la Recherche et l'Enseignement en Neurosciences; PD‐MCI: Parkinson's disease mild cognitive impairment; VA: Veteran's Affairs.