Gut microbiota changes associated with frailty in older adults: A systematic review of observational studies

Table 2 The Agency for Healthcare Research and Quality assessment for the cross-sectional study

Ref.	Item 1	Item 2	Item 3	Item 4	Item 5	Item 6	Item 7	Item 8	Item 9	Item 10	Item 11	Scores
Picca et al[19], 2020	Yes	Yes		Yes	Yes			Yes		Yes		6
Van Tongeren et al[16], 2005	Yes	Yes		Yes	Yes		Yes			Yes		6
Xu et al[17], 2021	Yes			Yes	Yes		Yes	Yes		Yes		6
Lim et al[18], 2021	Yes	Yes			Yes		Yes	Yes		Yes		6
Zhang et al[22], 2020	Yes	Yes		Yes	Yes	Yes	Yes	Yes		Yes		8
Margiotta et al[20], 2020	Yes	Yes		Yes	Yes		Yes	Yes		Yes		7
Zhang et al[21], 2022	Yes	Yes	Yes		Yes	Yes	Yes	Yes				7

Yes is one point, the total number of stars represents a number of points. Item 1: Define the source of information (survey, record review)? Item 2: Inclusion and exclusion criteria for exposed and unexposed subjects (cases and controls) or refer to previous publications? Item 3: Indicate time period used for identifying patients? Item 4: Indicate whether or not subjects were consecutive if not population-based? Item 5: Indicate if evaluators of subjective components of study were masked to other aspects of the status of the participant? Item 6: Describe any assessments undertaken for quality assurance purposes (e.g., testretest of primary out come measuroments)? Item 7: Explain any patient exclusions from analysis? Item 8: Describe how confounding was assessed and/or controlled? Item 9: If applicable, explain how missing data were handled in the analysis? Item 10: Summarize patient response rates and completeness of data collection? Item 11: Clarify what follow-up, if any, was expected and the percentage of patients for which incomplete data or follow-up was obtained?