Reconceptualizing autonomic function testing in migraine: a systematic review and meta-analysis

Table 1 Assessment of risk of bias according to Hoy et al. [46]

References	Year	Assessment criteria of study bias^a
References	Year	1	2	3	4	5	6	7	8	9	10	11
Boiardi et al. [4]	1988	High	Moderate	Low	Moderate	Low	Low	Low	Low	High	Low	Moderate
Havanka-Kanniainen et al. [51]	1986	Moderate	Moderate	Low	Low	Low	Low	Low	Low	High	Low	Moderate
Havanka-Kanniainen et al. [52]	1986	High	Moderate	Low	Moderate	Low	Low	Low	Low	High	Low	Moderate
Havanka-Kanniainen et al. [53]	1987	Moderate	Moderate	Low	Low	Low	Low	Low	Low	Moderate	Low	Low
Havanka-Kanniainen et al. [54]	1988	Low	Moderate	Low	Moderate	Low	Low	Low	Low	High	Low	Moderate
Pogacnik et al. [56]	1993	Moderate	Moderate	Low	Moderate	Low	Low	Low	Low	High	Low	Moderate
Qavi et al. [57]	2023	Moderate	Moderate	Low	Moderate	Low	Low	Low	Low	High	Low	Moderate

^aExternal validity (1–4): (1) Was the study’s target population a close representation of the national population in relation to relevant variables, e.g. age, sex, occupation? (2) Was the sampling frame a true or close representation of the target population? (3) Was some form of random selection used to select the sample OR was a census undertaken? (4): Was the likelihood of non-response bias minimal? Internal validity (5–10): (5) Were data collected directly form the subjects? (6) Was an acceptable case definition used in the study? (7) Was the instrument that measured the parameter of interest shown to have reliability and validity (if necessary)? (8) Was the same mode of data collection used for all subjects? (9) Was the length of the shortest prevalence period for the parameter of interest appropriate? (10) Were numerator(s) and denominator(s) for the parameter of interest appropriate? Summary item on the overall risk of study bias (11): (11) Low risk of bias: further research is very unlikely to change our confidence in the estimate. Moderate risk of bias: further research is likely to have an important impact on our confidence in the estimate and may change the estimate. High risk of bias: further research is very likely to have an important impact on our confidence in the estimate and is likely to change the estimate

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