Using electronic patient records to assess the effect of a complex antenatal intervention in a cluster randomised controlled trial—data management experience from the DESiGN Trial team

Table 6 Comparison of summary statistics between trial phases and intervention allocation

	Pre-randomisation phase				Trial comparison phase
	Control sites		Intervention sites		Control sites		Intervention sites
	Observed data	Imputed dataset	Observed data	Imputed dataset	Observed data	Imputed dataset	Observed data	Imputed dataset
Maternal height (median [IQR])	1.64 [1.60, 1.68]	1.64 [1.60, 1.69]	1.63 [1.58, 1.68]	1.63 [1.58, 1.68]	1.64 [1.60, 1.69]	1.64 [1.60, 1.69]	1.64 [1.60, 1.69]	1.63 [1.59, 1.68]
Maternal weight (median [IQR])	66.0 [58.8, 76.0]	66.0 [58.5, 76.0]	64.5 [57.0, 74.0]	64.7 [57.3, 74.4]	67.2 [59.9, 78.0]	67.0 [59.5, 77.9]	67.2 [59.9, 78.0]	65.4 [58.0, 76.0]
Ethnicity^a:
White (%)	62.4%	62.8%	46.9%	50.2%	62.4%	62.7%	50.2%	50.6%
Black (%)	16.6%	16.2%	12.4%	11.8%	15.4%	15.1%	10.8%	10.9%
Asian (%)	13.4%	13.3%	27.1%	24.8%	13.5%	13.5%	25.2%	24.6%
Mixed (%)	2.2%	2.1%	1.6%	1.6%	2.6%	2.6%	1.3%	1.3%
Other (%)	5.4%	5.5%	12.1%	11.6%	6.1%	6.1%	12.5%	12.6%
Parity (% multiparous)	49.4%	53.7%	46.8%	46.5%	48.8%	52.5%	48.8%	51.6%
Neonatal birthweight in grams (median [IQR])	3380 [3050, 3700]	3380 [3050, 3700]	3340 [3010, 3660]	3340 [3010, 3660]	3360 [3040, 3670]	3360 [3035, 3670]	3320 [3000, 3645]	3320 [2996, 3645]
Neonatal gestational age at birth in weeks (median [IQR])	40 [39, 41]	40 [39, 41]	40 [39, 41]	40 [39, 41]	40 [39, 41]	40 [39, 41]	40 [39, 41]	40 [39, 41]

^aFive categories of ethnicity presented here for brevity, but ethnicity imputed according to categories used by the foetal/neonatal weight customised centile calculator, e.g. British European, Central African, Chinese, Mixed Asian-European

ISSN: 1745-6215