Standardising the measurement of physical activity in people receiving haemodialysis: considerations for research and practice

Table 2 Changes in step count per HD and non-HD day, intraclass correlation coefficients and number of days of activity monitoring required to obtain representative PA data across a range of minimum wear time criteria

	HD step count				ICCs	Number of days needed^a	Number of days needed^b	Non-HD step count				ICCs	Number of days needed^a	Number of days needed^b
Wear time criteria (hours)	N	Day 1	Day 2	Day 3				N	Day 1	Day 2	Day 3
≥ 1	62	3249 ± 3481	3896 ± 3266	3050 ± 3195	0.723	1.53	2	65	5126 ± 5173	3499 ± 3992	4906 ± 4688	0.559	3.16	4
≥ 2	60	3318 ± 3518	3993 ± 3272	3139 ± 3210	0.719	1.56	2	64	5023 ± 4977	3462 ± 4026	4713 ± 4458	0.586	2.83	3
≥ 3	57	3308 ± 3610	3986 ± 3355	3207 ± 3270	0.723	1.53	2	63	5024 ± 5017	3517 ± 4034	4714 ± 4494	0.588	2.80	3
≥ 4	55	3288 ± 3670	3912 ± 3350	3241 ± 3299	0.744	1.38	2	63	5024 ± 5017	3517 ± 4034	4714 ± 4494	0.588	2.80	3
≥ 5	52	3514 ± 3694	4096 ± 3367	3541 ± 3274	0.729	1.49	2	63	5024 ± 5017	3517 ± 4034	4714 ± 4494	0.588	2.80	3
≥ 6	44	3676 ± 3897	4091 ± 3519	3744 ± 3412	0.764	1.24	2	62	5066 ± 5046	3511 ± 4067	4688 ± 4526	0.591	2.77	3
≥ 7	38	3340 ± 3561	4030 ± 3720	3748 ± 3484	0.815	0.91	1	62	5066 ± 5046	3511 ± 4067	4688 ± 4526	0.591	2.77	3
≥ 8	32	3382 ± 3811	4300 ± 3939	3817 ± 3733	0.827	0.84	1	61	5317 ± 5232	3522 ± 3974	4775 ± 4524	0.614	2.51	3
≥ 9	28	3750 ± 3942	4455 ± 4127	4099 ± 3891	0.831	0.81	1	61	5317 ± 5232	3522 ± 3974	4797 ± 4518	0.615	2.50	3
≥ 10	25	3998 ± 4098	4584 ± 4275	4107 ± 4011	0.847	0.72	1	61	5317 ± 5232	3522 ± 3974	4797 ± 4518	0.615	2.50	3
≥ 11	15	3855 ± 3983	4707 ± 4348	4338 ± 4584	0.875	0.57	1	59	5456 ± 5314	3524 ± 3950	4885 ± 4555	0.602	2.64	3
≥ 12	11	3270 ± 3427	4479 ± 4434	3962 ± 4576	0.839	0.77	1	53	5712 ± 5457	3601 ± 4086	5211 ± 4680	0.611	2.55	3

ICC Intraclass correlation coefficients, HD Haemodialysis. ^aA minimum number of days needed to achieve an ICC of 0.80 calculated using the Spearman-Brown prophecy formula; ^bEstimates from the Spearman-Brown prophecy formula should be rounded up (e.g. an estimate of at least 1.2 days should be interpreted as at least 2 days because 1 will be insufficient to achieve an ICC ≥ 0.8

ISSN: 1471-2369