Table 4.

Response to second reminder in RCT B by first reminder received

	Full questionnaire				Postcard
	Full questionnaire		Abridged questionnaire		Full questionnaire		Abridged questionnaire
	N = 221		N = 110		N = 253		N = 126
	n	%	n	%	n	%	n	%
Completed questionnaires returned	18	8.1	10	9.1	16	6.3	25	19.8
Absolute percentage difference (95% CI) compared to full questionnaire/full questionnaire combination; p-value
Full/Abridged	-1.0 (− 7.6, 5.5); 0.77
Postcard/Full	1.8 (−2.9, 6.5); 0.45
Postcard/Abridged	-11.7 (−19.5, -3.9); 0.002
Logistic regression model odds ratios (95% CI); p-value
Abridged	1.13 (0.50, 2.53); 0.77
Postcard	0.76 (0.38, 1.53); 0.45
Interaction (Abridged * Postcard)	3.25 (1.13, 9.29); 0.028