STROBE Statement—Checklist of items that should be included in reports of cross-sectional studies

Item No	Recommendation
Title and abstract	1	(a) Indicated the study’s design in the abstract
(b) Provided in the abstract an informative and balanced summary of what was done and what was found
Introduction
Background/rationale	2	Explained the scientific background and rationale for the investigation being reported
Objectives	3	Stated specific objectives, including any prespecified hypotheses
Methods
Study design	4	Presented key elements of study design early in the paper
Setting	5	Described the setting, locations, and relevant dates, including periods of recruitment, exposure, follow-up, and data collection
Participants	6	(a) Gave the eligibility criteria, and the sources and methods of selection of participants (See “Study design, ethics statement, data set, and HLA typings formats” section)
Variables	7	Clearly defined all first two field HLA genotype imputation performance parameters
Data sources/ measurement	8*	For each variable of interest, gave sources of data and details of methods of assessment (See section entitled “Validation of first field to first two fields HLA type imputation by HaploStats and Supplementary material”)
Bias	9	Described efforts to address potential sources of bias (See section entitled “Verification of Hardy-Weinberg Equilibrium (HWE) and generalizability of findings across Quebec HSCD”)
Study size	10	Explained how the study size was arrived at (See section entitled “Study design, ethics statement, data set, and HLA typings formats”)
Quantitative variables	11	Explained how quantitative variables were handled in the analyses. If applicable, describe which groupings were chosen and why (See section entitled “Validation of first field to first two fields HLA type imputation by HaploStats and Supplementary material”)
Statistical methods	12	(a) Described all statistical methods
(b) Explained how missing data were addressed
(c) Described analytical methods taking account of sampling strategy
(See sections entitled “Validation of first field to first two fields HLA type imputation by HaploStats and Supplementary material”, “Study design, ethics statement, data set, and HLA typings formats”, and “Verification of Hardy-Weinberg Equilibrium (HWE) and generalizability of findings across Quebec HSCD”, respectively)
Results
Participants	13*	(a) Reported numbers of individuals at each stage of study—eg numbers potentially eligible, examined for eligibility, confirmed eligible, included in the study, completing follow-up, and analysed
(b) Gave reasons for non-participation at each stage
(c) Considering simplicity of study flow, a diagram was not deemed necessary
Descriptive data	14*	(a) The only characteristic available in the Hema-Quebec registry that was required for our study was participants’ race.
Outcome data	15*	Imputation performance characteristics are reported
Main results	16	(a) Imputation performance is reported
Other analyses	17	We report on analyses for verification of Hardy-Weinberg Equilibrium (HWE) and generalizability of findings across Quebec HSCD
Discussion
Key results	18	Summarised key results with reference to study objectives
Limitations	19	Limitations of the study, sources of potential bias or imprecision are discussed.
Interpretation	20	A cautious overall interpretation of results is provided, which considers objectives, limitations, analyses, and other relevant evidence
Generalisability	21	The generalisability of the study results is discussed
Other information
Funding	22	Source of funding is provided