dabl Educational Trust Validation Checklist Device Judgement Recommended Manufacturer IEM Device Stabil O Graph Category Upper Arm (Self) Mode Oscillometric Protocol Reference BHS + ESH Westhoff TH, Schmidt S, Zidek W, van der Giet M. Validation of the Stabil O Graph blood pressure self measurement device Journal of Human Hypertension 2007;22,233 235,Research Letter Recruitment Screened 112 (BHS), 41 (ESH) Included 85 (BHS), 33 (ESH) Excluded Explained Some Ranges Correct Yes Ages Correct Yes Sexes Correct Yes Description of Methods Good Procedure Description Good Problems Explained Results Description Good Plots Plots are absent from the letter. These were requested and are included below. Result Pass Both BHS and ESH and also on ESH subgroup from BHS sample Signoff Notes Without plots or subsections, the letter format is not an ideal method of prsenting the results but it does benefit from consiseness. Problems with a fall in pressure in the ESH study high range subjects are addressed with a confirmatory analyis using a subset from BHS study subjects. Date 14/5/2008 Plots and were requested from the authors. These and tables from the original manuscript are included below. 2007 dabl Educational Trust., 34 Main Street, Blackrock, Co. Dublin
Tables Table 1A: Number of patients required and number of patients examined in each blood pressure group of the BHS protocol Systolic BP Diastolic BP Minimum Number of Number of (mmhg) (mmhg) number of subjects subjects subjects examined examined required (systolic) (diastolic) < 100 < 60 8 8 10 100-129 60-79 20 26 22 130-160 80-100 20 21 24 161-180 101-110 20 21 20 >180 >110 8 9 9 Table 1B: Grading criteria of the BHS. To obtain a grade, the device must achieve percentages those reported in the table in all the three categories. Grade Percentage of readings with differences between standard and test device of 5 mmhg 10 mmhg 15 mmhg A 60% 85% 95% B 50% 75% 90% C 40% 65% 85% D Worse than C Worse than C Worse than C 17
Table 1C: Results of the BHS validation procedure, n=85 subjects. Numbers in column 1 correspond to number of measurement in the BHS protocol (Device measurements versus preceding and succeding Observer measurements) Mean ± SD of Grade 5 10 15 30 Mean ± SD (mmhg) differences (mmhg) Observer 1 SBP (1 vs 2, 3 vs 4, 5 vs 6) DBP (1 vs 2, 3 vs 4, 5 vs 6) SBP (2 vs 3, 4 vs 5, 6 vs 7) DBP (2 vs 3, 4 vs 5, 6 vs 7) Observer 2 SBP (1 vs 2, 3 vs 4, 5 vs 6) DBP (1 vs 2, 3 vs 4, 5 vs 6) SBP (2 vs 3, 4 vs 5, 6 vs 7) DBP (2 vs 3, 4 vs 5, 6 vs 7) Final grading B 61% 88% 94% 100% 138.4 ± 30.6-3.1 ± 7.2 A 67% 94% 98% 100% 83.9 ± 16.2 0.1 ± 5.8 A 66% 89% 96% 100% 137.2 ± 30.2-1.9 ± 6.6 A 67% 95% 99% 100% 83.5 ± 16.2 0.5 ± 5.6 B 61% 88% 93% 100% 138.5 ± 30.7-3.2 ± 7.3 A 65% 94% 98% 100% 84.0 ± 16.5 0.0 ± 5.8 B 66% 87% 94% 100% 137.2 ± 30.2-1.9 ± 6.6 A 64% 96% 99% 100% 83.5 ± 16.4 0.5 ± 5.8 SBP A 66% 89% 96% 100% 137.2 ± 30.2-1.9 ± 6.6 DBP A 65% 94% 98% 100% 84.0 ± 16.5 0.0 ± 5.8 18
Table 2A: Number of measurements required and achieved for systolic (SBP) and diastolic (DBP) blood pressure falling in specified error-categories according to phase 1 of the ESH protocol (number of subjects n=15, number of measurements n=45). Error category < 5 mmhg < 10 mmhg < 15 mmhg Required One of 25 35 40 Achieved SBP 32 42 45 DBP 34 39 43 Table 2B: Number of measurements required and achieved for systolic (SBP) and diastolic (DBP) blood pressure falling in specified error-categories according to phase 2.1 of the ESH protocol (number of subjects n=33, number of measurements n=99). Error category < 5 mmhg < 10 mmhg < 15 mmhg Required Two of 65 80 95 All of 60 75 80 Achieved SBP 72 92 99 DBP 75 90 97 19
Table 2C: Number of subjects having the ESH-specified fraction of device-observer differences 5 mmhg for systolic (SBP) and diastolic (DBP) blood pressure (number of subjects 33) Subjects with specified fraction of device-observer differences 2/3 < 5 mmhg 0/3 < 5 mmhg Required Both 22 3 Achieved SBP 25 3 DBP 27 1 20
Table 3: Number of subjects obtained for each blood pressure category according to ESH and BHS criteria in the categorization measurement (BPA) and the following validation measurements (BP1 BP7) BPA BP1 BP3 BP5 BP7 ESH Systolic 90-129 mmhg 11 15 14 16 15 130-160 mmhg 11 15 17 15 17 161-180 mmhg 11 3 2 2 1 Diastolic 40-79 mmhg 11 12 13 13 13 80-100 mmhg 11 15 18 16 16 101-130 mmhg 11 6 2 4 4 BHS Systolic <100 mmhg 8 7 7 7 6 100-129 mmhg 26 30 31 32 32 130-160 mmhg 21 23 23 23 25 161-180 mmhg 21 16 17 18 18 >180 mmhg 9 9 7 5 4 Diastolic < 60 mmhg 10 8 7 7 7 60-79 mmhg 22 25 29 26 29 80-100 mmhg 24 32 29 39 36 101-110 mmhg 20 18 17 9 10 >110 mmhg 9 2 3 4 3 21
Figure legends Figure 1: Tukey mean-difference plots (BHS validation process) of systolic (A) and diastolic (B) blood pressure difference of device and observer in 85 subjects (n=255 measurements). Mean difference for systolic blood pressure is -1.9 ± 6.6 mmhg, mean difference for diastolic blood pressure is 0.1 ± 5.8 mmhg. Figure 2: Tukey mean-difference plots (ESH validation process) of systolic (A) and diastolic (B) blood pressure difference of device and observer in 33 subjects (n=99 measurements). Mean device-observer differences were 0.0 ± 5.6 mmhg (systolic) and 1.0 ± 5.7 mmhg (diastolic). 24
Figures Figure 1A 25
Figure 1B 26
Figure 2 Figure 2A Figure 2B 27