Clustering of continuous and binary outcomes at the general practice level in individually randomised studies in primary care - a review of 10 years of primary care trials

Table 4 ICC for outcome measures collected in multiple studies

Outcome measure	N	Unadjusted median (IQR)	Adjusted median (IQR)
Symptom severity	9	0.01 (0.00, 0.08)	0.00 (0.00, 0.03)
Reconsultation	6	0.01 (0.00, 0.08)	0.01 (0.00, 0.07)
HADS anxiety^c	2	0.09 (0.00, 0.19)	0.04 (0.02, 0.05)
HADS depression	2	0.04 (0.02, 0.07)	0.02 (0.00, 0.05)
Patient Enablement Instrument (PEI)	2	0.02 (0.02, 0.02)	^d
Tympanometric resolution	2	0.02 (0.00, 0.03)	0.02 (0.00, 0.03)
EQ 5D-3 L	8	0.02 (0.01, 0.03)	0.01 (0.01, 0.04)

^cHADS Hospital Anxiety and Depression Scale
^dPEI is only collected at follow up time points so no baseline adjustment is possible

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