CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 2, March 2012
86
AFRICA
Osun State, Nigeria over a two-month period (1 February to 31
March 2010). In our hypertension clinic, a patient’s blood pres-
sure is first taken by a nurse using a mercury sphygmomanome-
ter and the value is recorded in the patient’s folder. The physician
repeats the BP measurement during the same visit as part of the
clinical evaluation of the patient.
Only folders of patients with at least three clinic visits before
the commencement of the study and with proper documentation
of the BP values by nurses and doctors were selected for the
study. The latest three BP readings by the nurses and doctors
were extracted from the medical records of the patients.
The designation of the attending doctor at each clinic visit
was also recorded. The nurses involved in BP measurements
of patients in our clinic during the study period were registered
nurses and they were in the same cadre. Ten doctors and two
nurses were responsible for taking the readings included in this
analysis.
Patients’ gender, age, height (m) and latest weight (kg) were
recorded. Body mass index (BMI) was calculated from weight/
height
2
(kg/m
2
).
Ethical approval for the study was obtained from the Research
Ethics Committee of Ladoke Akintola University of Technology
Teaching Hospital, Osogbo, Osun State, Nigeria.
Statistical analysis
Continuous variables were summarised as means
±
standard
deviation and categorical variables were displayed as percent-
ages. Distribution of end digits of systolic and diastolic blood
pressure values was noted and Chi-square comparison was
performed to examine the significant differences in the occur-
rence of 0, 2, 4, 5, 6 and 8 end digits reported for both systolic
and diastolic BP readings by nurses and doctors. Differences in
zero and non-zero end digits of BP values by different cadres of
doctors were also evaluated.
The last clinic attendance BP value was used to assess the
demographic characteristics of patients that may influence EDP
by physicians. The demographic parameters were compared
using Chi-square for categorical and Student’s
t
-test for continu-
ous variables in the group of patients with zero EDP and the
group with non-zero end digits. All
p
-values less than 0.05 were
considered to be statistically significant.
Statistical analysis was done using Statistical Package for
Social Sciences (SPSS) software, version 15 (SPSS, Chicago,
IL, USA). Figures were drawn using the Microsoft Office Excel
2007 version.
Results
The study population consisted of 114 patients (37 males and 77
females) and their demographic features are shown in Table 1.
The female preponderance of the study population (female:male
was 2.1:1) reflects the clinic attendance of our patients through-
out the year. The male patients were significantly older and taller
than the females. However, the female patients had higher BMI
than the males.
There was no statistically significant difference in the mean
SBP and DBP of males and females. The means of the nurse–
doctor SBP difference and nurse–doctor DBP difference were
–4.36 mmHg (range –60 to
+
32 mmHg) and 1.22 mmHg (range
–44 to +40 mmHg), respectively.
The nurses and the doctors took 342 BP readings each. Table
2 shows the distribution of the end digits of the systolic and dias-
tolic blood pressure readings. The distribution of end digits for
SBP readings by nurses revealed that 98.5% ended in the digit 0;
0.3% ended in the digit 4; and 1.2% in the digit 5. On the other
hand, 51.2% of the SBP readings of doctors ended in the digit
0; 14.3% in the digit 4; and 16.4% in the digit 6. None of the
doctors’ readings ended with the digit 5.
Nurses had a statistically significantly higher occurrence of
SBP zero EDP compared to doctors (
p
<
0.001). For DBP, 98.5%
of nurses’ readings ended in the digit 0 while 64.3% of doctors’
readings ended in the digit 0 (
p
<
0.001).
Figs 1 and 2 show the distribution of EDP for SBP and DBP
readings, respectively, among different cadres of doctors. The
consultant staff showed the least preference for end-digit 0 when
compared with registrars and senior registrars. While 25.4% of
TABLE 1. DEMOGRAPHICAND CLINICAL CHARACTERISTICS OF THE STUDY POPULATION
Patients’ characteristics
Male (
n
=
37)
Female (
n
=
77)
Total (
n
=
114)
Range
p
-value
Age (years)
68.1
±
11.8
59.9
±
11.9
62.5
±
12.5
23–85
0.001
Weight (kg)
69.1
±
11.3
71.5
±
17.2
70.8
±
15.5
43–120
0.438
Height (m)
1.69
±
0.06
1.60
±
0.06
1.63
±
0.07
1.46–1.81
<
0.001
BMI (kg/m
2
)
24.4
±
4.6
28.1
±
6.2
26.9
±
6.0
15.8–42.8
0.001
Nurses’ mean SBP (mmHg)
132.7
±
23.9
136.0
±
22.5
134.9
±
22.9
90–210
0.479
Doctors’ mean SBP (mmHg)
136.9
±
24.6
140.4
±
25.1
139.3
±
24.9
90–230
0.488
Nurses’ mean DBP (mmHg)
78.9
±
16.6
82.8
±
14.0
81.5
±
15.0
50–130
0.195
Doctors’ mean DBP (mmHg)
80.0
±
12.3
80.5
±
13.5
80.3
±
13.0
54–120
0.835
Mean nurse–doctor SBP difference
–4.22
±
20.19
-4.42
±
20.49
-4.36
±
20.31
–60 to +32
0.959
Mean nurse–doctor DBP difference
–1.03
±
12.63
2.31
±
13.46
1.22
±
13.23
–44 to 40
0.209
TABLE 2. DISTRIBUTION OF END DIGITS OF SYSTOLIC
AND DIASTOLIC BLOOD PRESSURE READINGS BY
DOCTORSAND NURSES
End digit
Systolic blood pressure
readings
Diastolic blood pressure
readings
Nurses (%) Doctors (%) Nurses (%) Doctors (%)
0
337 (98.5)* 175 (51.2) 337 (98.5)** 220 (64.3)
2
0 (0)
33 (9.6)
0 (0)
15 (4.4)
4
1 (0.3)
49 (14.3)
1 (0.3)
46 (13.5)
5
4 (1.2)
0 (0)
1 (0.3)
0 (0)
6
0 (0)
56 (16.4)
0 (0)
32 (9.4)
8
0 (0)
29 (8.5)
3 (0.9)
29 (8.5)
Total
342 (100)
342 (100)
342 (100)
342 (100)
*
χ
2
=
219.3,
p
<
0.001; **
χ
2
=
136.7,
p
<
0.001.
