Table 1B.

Definitions, cut-points and per cent adherence/compliance across studies. Studies were placed into subgroups according to the method used to measure adherence. Scale and cut-points used to rate adherence are also shown.

Studies	Outcome	Definition/scale	Cut-point for adherence/ compliance	Adherence %
Prescription claims
Sarawate et al, 200617	Compliance	MPR was calculated as medication supply actually received divided by medication supply that could have been received.	MPR≥80%	28
Briesacher et al, 200818	Adherence	MPR defined as the days supply of the drug dispensed during the follow-up year divided by the number of days in the year.	MPR≥80%	36.8
Harrold et al, 200924	Adherence	MPR defined as the days supply of medication dispensed during the follow-up year divided by the number of days in the year and is a reliable measure of adherence.	MPR≥80%	44
Halpern et al, 200930	Compliance	MPR: sum of days supply from first observed allopurinol fill during the 2-year observation period divided by the number of days between the first observed fill and the end of the postindex period.	MPR≥80%	44
Rashid et al, 201229	Adherence	Adherence was measured using the MPR over the follow-up time period.	MPR>80%	47.5*
Horsburgh et al, 201419	Adherence	MPR defined as the ratio of days supplied from initial dispensing to the number of days to the end of the study period or the patient’s date of death.	MPR≥80%	78*
Singh, 201423	Adherence	Self-report adherence to ULT.	MPR≥0.80	32.6*
McGowan et al, 201622	Adherence	MPR defined as the number of doses filled by the pharmacist divided by the number of days in the defined period (6 or 12 months).	MPR≥80%	45.5
Tan et al, 201632	Adherence	MPR summarised the proportion of days a patient has a supply of medications for.	MPR≥80%	83.5
Solomon et al, 200821	Adherence	PDC was calculated as the days with available UALT divided by the total number of days of follow-up.	PDC≥80%	36*
Park et al, 201226	Adherence	PDC defined as the number of days during the study period (365 days) that the patient had at least one gout-specific medication on hand.	PDC≥80%	26.9*
Zandman-Goddard et al, 201320	Adherence	Mean PDC calculated by dividing the quantity of allopurinol dispensed by the total time interval from index date to drug cessation, death, leaving MHS or 31 December 2009, whichever occurred first.	PDC≥80%	17
Mantarro et al, 201531	Adherence	PDC defined as dividing the cumulative days of medication use by the length of follow-up.	PDC≥80%	45.9
Rashid et al, 201527	Adherence	PDC was defined as the number of days with ULT drug dispensed divided by the number of days in the specified time interval (365 days).	PDC≥80%	48.2*
Kuo et al, 201528	Adherence	PDC defined as the period from the latest of registration date or 1 January to the earliest of transfer-out, death date or 31 December of the calendar year specified.	PDC≥80%	39.66
Riedel et al, 200425	Compliance	Compliance was defined for each prescription period as the presumed use of allopurinol on at least 80% of the days of that period.	Compliance rate≥80%	18
Pill count
Lee et al, 201633	Compliance	Pill counts: non-compliance was defined as <80% of the prescribed dose taken.	Pill count≥80%	71.2
Self-report
Silva et al, 201035	Compliance	Compliance defined as taking medication regularly, as prescribed.	NS	53*
Singh et al, 201634	Adherence	Number of days the patient forgot to take ULT in the last month.	Adherence>0.80	78.5
Tan et al, 201632	Adherence	MMAS-8 used to measure medication adherence (eight items, total score ranges 0–8).	MMAS-8 score≥6 (75%)	61.9
Interview
Martini et al, 201236	Compliance	Participants admitted to not taking ULTs as prescribed.	NS	79
Sheng et al, 201438	Adherence	Adherence was defined as sustained use of ULD in the prior 12 months, otherwise non-adherence.	NS	53.8*
van Onna et al, 201537	Adherence	Non-adherence at some point in time was defined as admission in the interview.	NS	50.0*

*Calculated based on data provided in the article.

MMAS-8, 8-item Morisky Medication Adherence Scale; MPR, medication possession ratio; NS, not stated; PDC, proportion of days covered; UALT, uric acid-lowering therapy; ULD, urate-lowering drug; ULT, urate-lowering therapy.