Khan 2011.

Methods	Allocation: randomised trial, alternation Design: parallel‐group
Participants	Number randomised: 62 Age range: 15 to 35 Gender: 74% males Setting: hospital, Pakistan Inclusion criteria: not specifically stated Exclusion criteria: other associated illness Participant characteristics: mean age = 24.6 years
Interventions	Needle aspiration versus incision and drainage Intervention group: needle aspiration n = 31 Comparator group: incision and drainage n = 31 Use of additional interventions: antibiotics (injection benzyl penicillin and metronidazole), analgesics
Outcomes	1. Recurrence rate 2. Length of hospital stay (Outcomes not specified as primary/secondary)
Funding sources	Not specified
Declarations of interest	Not specified
Notes	Needle aspiration failures treated with incision and drainage Participants lost to follow‐up: none
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation method not specified
Allocation concealment (selection bias)	Unclear risk	No allocation concealment specified
Blinding of participants and personnel (performance bias) All outcomes	High risk	No mention of blinding made; probably not done
Blinding of outcome assessment (detection bias) All outcomes	High risk	No mention of blinding made; probably not done
Incomplete outcome data (attrition bias) All outcomes	Low risk	All patients presumably accounted for (admitted as inpatients); no dropouts stated
Selective reporting (reporting bias)	Unclear risk	Insufficient information to permit a judgement of high or low risk
Other bias	Unclear risk	Not enough data to assess other risk of bias. Incomplete methodological description (definition of recurrence/criteria for re‐intervention not described, timing of assessment for recurrence not described).