Self-monitoring of lower leg skin temperature: accuracy of self-reported data and adherence to a cooling protocol for the prevention of venous leg ulcers

Figures & data

Figure 1 Monthly study log.

Table 1 Demographics

Demographicsa	Intervention group n=54	Control group n=46	P-value
Age, years, mean (SD)	64.6 (11.0)	61.7 (10.8)	0.19
Sex			0.42
Male	23 (42.6)	16 (34.8)
Female	31 (57.4)	30 (65.2)
Race			0.85
White	15 (27.8)	12 (26.1)
Black/African American	39 (72.2)	34 (73.9)
Employment			0.73
Employed (full or part time)	11 (20.4)	10 (21.7)
Not employed	12 (22.2)	13 (28.3)
Retired	31 (57.4)	23 (50.0)
Education			0.51
High school or less or missing	21 (38.9)	16 (34.8)
High school graduate	25 (46.3)	19 (41.3)
Some college or college graduate	8 (14.8)	11 (23.9)
Marriage status			0.12
Not married	28 (51.9)	31 (67.4)
Married	26 (48.2)	15 (32.6)
Residence			0.84
Rural	21 (38.9)	17 (37.0)
Urban	33 (61.1)	29 (63.0)

Notes:

a N (%) unless otherwise noted; there are no significant differences between groups, P>0.05. Due to rounding, percentages may not sum to 100%.

Abbreviation: SD, standard deviation.

Figure 2 CONSORT flow diagram.

Abbreviation: CONSORT, consolidated standards of reporting trials.

Table 2 Returned participant study logs error typology

Error typea	Returned logs
	N=826
	n	%
White-outs, cross-offs and/or overwrites	489	59.2
Entries omitted (temperatures and/or before or after treatment times)	288	34.9
Morning leg skin temperature monitoring not performed	243	29.4
Cooling intervention not performed per protocol	237	28.7
Extraneous data recorded	221	26.8
Recorded cooling intervention time not per protocol (<30 or >40 minutes)	208	25.2
Wrong monthly/weekly sheet used	92	11.1
Suspected fabrication of data (patterns of columned handwriting, etc)	71	8.6
Not all monthly/weekly sheets returned	71	8.6
Illegible hand writing	68	8.2
Questionable validity of data (severely extreme values, etc)	63	7.6
Use of dittos or arrows	55	6.7
Data recorded in wrong box	38	4.6
Freezer temperature not maintained per protocol at 0°C (±2°C)	38	4.6
Monthly log returned but completely unusable	36	4.4
Weekly sheets returned in wrong order	29	3.5
Multiple data entry in the same box	17	2.1
Monthly logs returned blank	16	1.9

Note:

a Error types are not mutually exclusive, therefore percentages do not sum to 100%.

Table 3 Average accuracy of participant monthly study logs by demographics

	Intervention group				Control group				All groups
	N	<85%	85%–99%	100%	N	<85%	85%–99%	100%	N	<85%	85%–99%	100%
Total sample	54	10 (18.5%)	30 (55.6%)	14 (25.9%)	46	12 (26.1%)	23 (50.0%)	11 (23.9%)	100	22 (22.0%)	53 (53.0%)	25 (25.0%)
Age, years, mean (SD)	54	70.0 (9.3)	65.0 (12.0)	59.8 (8.3)	46	61.8 (12.8)	60.7 (10.4)	63.7 (10.1)	100	65.5 (11.9)	63.2 (11.4)	61.5 (9.1)
Sex
Male	23	3 (13.0%)	16 (69.6%)	4 (17.4%)	16	5 (31.3%)	6 (37.5%)	5 (31.3%)	39	8 (20.5%)	22 (56.4%)	9 (23.1%)
Female	31	7 (22.6%)	14 (45.2%)	10 (32.3%)	30	7 (23.3%)	17 (56.7%)	6 (20.0%)	61	14 (23.0%)	31 (50.8%)	16 (26.2%)
Race
Black/African American	39	8 (20.5%)	22 (56.4%)	9 (23.1%)	34	9 (26.5%)	18 (52.9%)	7 (20.6%)	73	17 (23.3%)	40 (54.8%)	16 (21.9%)
White	15	2 (13.3%)	8 (53.3%)	5 (33.3%)	12	3 (25.0%)	5 (41.7%)	4 (33.3%)	27	5 (18.3%)	13 (48.1%)	9 (33.3%)
Marital status
Not married	28	5 (17.9%)	17 (60.7%)	6 (21.4%)	31	10 (32.3%)	16 (51.6%)	5 (16.1%)	59	15 (25.4%)	33 (55.9%)	11 (18.6%)
Live with partner	26	5 (19.2%)	13 (50.0%)	8 (30.8%)	15	2 (13.3%)	7 (46.7%)	6 (40.0%)	41	7 (17.1%)	20 (48.8%)	14 (34.1%)
Education
Less than high school	13	5 (38.5%)	7 (53.9%)	1 (7.7%)	9	2 (22.2%)	5 (55.6%)	2 (22.2%)	22	7 (31.8%)	12 (54.5%)	3 (13.6%)
High school graduate	25	4 (16.0%)	15 (60.0%)	6 (24.0%)	19	5 (26.3%)	9 (47.4%)	5 (26.3%)	44	9 (20.5%)	24 (54.5%)	11 (25.0%)
More than high school	16	1 (6.3%)	8 (50.0%)	7 (43.8%)	18	5 (27.8%)	9 (50.0%)	4 (22.2%)	34	6 (17.6%)	17 (50.0%)	11 (32.4%)
Employment
Not employed	43	9 (20.9%)	23 (53.5%)	11 (25.6%)	36	11 (30.6%)	16 (44.4%)	9 (25.0%)	79	20 (25.3%)	39 (49.4%)	20 (25.3%)
Employed	11	1 (9.1%)	7 (63.6%)	3 (27.3%)	10	1 (10.0%)	7 (70.0%)	2 (20.0%)	21	2 (9.5%)	14 (66.7%)	5 (23.8%)
Type of job helda
Professional	21	2 (9.5%)	11 (52.4%)	8 (38.1%)	21	5 (23.8%)	12 (57.1%)	4 (19.0%)	42	7 (16.7%)	23 (54.8%)	12 (28.6%)
Technical	13	3 (23.1%)	9 (69.2%)	1 (7.7%)	14	4 (28.6%)	6 (42.9%)	4 (28.6%)	27	7 (25.9%)	15 (55.6%)	5 (18.5%)
Manual	16	3 (18.8%)	8 (50.0%)	5 (31.3%)	8	2 (25.0%)	4 (50.0%)	2 (25.0%)	24	5 (20.8%)	12 (50.0%)	7 (29.2%)
Other	4	2 (50.0%)	2 (50.0%)	0 (0.0%)	3	1 (33.3%)	1 (33.3%)	1 (33.3%)	7	3 (42.9%)	3 (42.9%)	1 (14.3%)
Residence
Rural	21	1 (4.8%)	12 (57.1%)	8 (38.1%)	17	4 (23.5%)	10 (58.8%)	3 (17.6%)	38	5 (13.2%)	22 (57.9%)	11 (28.9%)
Urban	33	9 (27.3%)	18 (54.6%)	6 (18.2%)	29	8 (27.6%)	13 (44.8%)	8 (27.6%)	62	17 (27.4%)	31 (50.0%)	14 (22.6%)
Volunteered beforeb
Yes	5	3 (60.0%)	1 (20.0%)	1 (20.0%)	5	1 (20.0%)	2 (40.0%)	2 (40.0%)	10	4 (40.0%)	3 (10.0%)	3 (30.0%)
No	49	7 (14.3%)	29 (59.2%)	13 (26.5%)	41	11 (26.8%)	21 (51.2%)	9 (22.0%)	90	18 (20.0%)	50 (55.6%)	22 (24.4%)

Notes:

a Current or previous job held.

b Volunteered for research study before. There are no significant differences between groups, P>0.05.

Abbreviation: SD, standard deviation.

Table 4 Average accuracy of participant monthly study logs by end-of-study satisfaction survey

Difficulty of procedures	Intervention group				Control group
	N	<85%	85%–99%	100%	N	<85%	85%–99%	100%
Total sample	54	10 (18.5%)	30 (55.6%)	14 (25.9%)	46	12 (26.1%)	23 (50.0%)	11 (23.9%)
DVD instruction score
<10	0	0 (0.0%)	0 (0.0%)	0 (0.0%)	0	0 (0.0%)	0 (0.0%)	0 (0.0%)
10–15	7	0 (0.0%)	6 (85.7%)	1 (14.3%)	9	3 (33.2%)	3 (33.2%)	3 (33.2%)
16 (perfect score)	45	10 (22.2%)	23 (51.1%)	12 (26.7%)	35	8 (22.9%)	19 (54.3%)	8 (22.9%)
Treatment
Easy/somewhat easy	48	10 (20.8%)	26 (54.2%)	12 (25.0%)	45	11 (24.4%)	23 (51.1%)	11 (24.4%)
Difficult/somewhat difficult	5	0 (0.0%)	3 (60.0%)	2 (40.0%)	1	1 (100.0%)	0 (0.0%)	0 (0.0%)
Leg-cuff use
Easy/somewhat easy	46	8 (17.4%)	25 (54.4%)	13 (28.3%)	43	10 (23.3%)	22 (51.2%)	10 (34.5%)
Difficult/somewhat difficult	7	2 (28.6%)	4 (57.1%)	1 (14.3%)	3	2 (66.7%)	1 (33.3%)	0 (0.0%)
Comfortable to elevate
Yes	34	7 (19.4%)	15 (41.7%)	12 (33.3%)	27	7 (24.1%)	10 (34.5%)	11 (25.6%)
No	2	0 (0.0%)	2 (5.6%)	0 (0.0%)	2	0 (0.0%)	2 (6.9%)	0 (0.0%)
Thermometer use
Easy/somewhat easy	52	10 (19.2%)	28 (53.9%)	14 (26.9%)	46	12 (26.1%)	23 (50.0%)	11 (23.9%)
Difficult/somewhat difficult	0	0 (0.0%)	0 (0.0%)	0 (0.0%)	0	0 (0.0%)	0 (0.0%)	0 (0.0%)
Study log use
Easy/somewhat easy	48	9 (18.8%)	25 (52.1%)	14 (29.2%)	44	11 (25.0%)	22 (50.0%)	11 (25.0%)
Difficult/somewhat difficult	4	1 (25.0%)	3 (75.0%)	0 (0.0%)	2	1 (50.0%)	1 (50.0%)	0 (0.0%)

Note: There are no significant differences between groups, P>0.05.

Figure 3 Mean monthly leg skin temperature difference before and after cooling treatment within the control group (placebo cuff) under ITT and mITT analysis.

Note: No statistical difference found between mITT and ITT analyses (P-value 1.0).
Abbreviations: ITT, intention-to-treat; mITT, modified intention-to-treat.

Figure 4 Mean monthly leg skin temperature difference before and after cooling treatment within the intervention group (cooling gel-cuff) under ITT and mITT analysis.

Note: No statistical difference found between mITT and ITT analyses (P-value 1.0).
Abbreviations: ITT, intention-to-treat; mITT, modified intention-to-treat.