Identifying the variables associated with pain during transrectal ultrasonography of the prostate

Figures & data

Figure 1 Image shows artifact caused by stool stored in the rectum and interfered with the image quality. The examiner cannot easily measure the prostate sagittal length.

Figure 2 Distribution of pain score.

Abbreviation: VAS, visual analog scale.

Figure 3 Kolmogorov–Smirnov test results showing that the pain score was normally distributed.

Table 1 Characteristics of the study population

Variable (number =498)	n (range)
Median age (years)	63 (43–87)
Median BMI	24.98 (16.8–47.06)
Median PSA (ng/mL)	5.03 (0.1–398.7)
Median prostate volume (mL)	32.40 (10.3–162.00)
Median prostatic sagittal length (cm)	4.50 (2.42–7.50)
Mean pain score (VAS)	2.87±2.02 (0–9)

Abbreviations: BMI, body mass index; PSA, prostate-specific antigen; VAS, visual analog scale.

Table 2 Comparison of patients’ numerical variables between pain score ≤3 and pain score ≥4

Characteristics	Pain score ≤3 mean ± SD	Pain score ≥4 mean ± SD	P-value
Age (years)	65.79±10.92	63.04±11.67	0.0293*
BMI	25.11±3.86	25.20±3.76	0.9314
Prostate volume (gm)	37.41±20.39	43.04±24.45	0.0161*
Prostate sagittal length (cm)	4.56±0.78	4.69±0.94	0.0415*
PSA (ng/mL)	3.24±2.17	4.85±3.82	0.8216

Notes: Comparisons were made using Mann–Whitney U-test.

* Indicates significant difference.

Abbreviations: BMI, body mass index; PSA, prostate-specific antigen; SD, standard deviation.

Table 3 Comparison of patients’ qualitative variables between pain score ≤3 and pain score ≥4

Characteristics	Pain score ≤3 (%)	Pain score ≤4 (%)	P-value
Previous TRUS experience (%)	23.85%	13.33%	0.0427*
Group 2 (%)	60.48%	34.91%	<0.0001*
External hemorrhoids (%)	26.67%	59.09%	<0.0001*
Prostate calcification (%)	22.11%	36.19%	0.0893
Previous anal operation (%)	6.96%	31.63%	<0.0001*
Stool artifact (%)	11.79%	22.85%	0.0068*

Notes: Comparisons were made using χ² test.

* Indicates significant difference.

Abbreviation: TRUS, transrectal ultrasound of the prostate.

Figure 4 Significantly lower pain scores of group 2 patients compared with those of group 1 patients.

Abbreviation: VAS, visual analog scale.

Table 4 Multivariate analysis for the pain associated with TRUS using linear regression analysis

Variable	β	SE (β)	P-value
Age (continuous variable)	−0.01381	0.0075	0.0671
BMI (continuous variable)	−1.001942	0.0209	0.9258
Prostate volume (continuous variable)	−0.00131	0.0020	0.6571
Prostate sagittal length (continuous variable)	0.005547	0.0021	0.0072*
PSA (continuous variable)	0.00002831	<0.001	0.717
Group 2 (vs group 1)	−0.4484	0.1570	0.0045*
Previous TRUS experience (vs absence of previous TRUS experience)	−0.4234	0.1932	0.0289*
External hemorrhoids (vs absence of external hemorrhoids)	1.261	0.1736	<0.0001*
Previous anal operation history (vs absence of anal operation history)	1.568	0.2476	<0.0001*
Prostate calcification (vs no calcification)	0.4528	0.1800	0.1122
Stool artifact (vs no stool artifact)	0.7174	0.2310	0.0021*

Notes:

* Indicates significant difference.

Abbreviations: TRUS, transrectal ultrasonography of the prostate; β, regression coefficient; SE, standard error; BMI, body mass index; PSA, prostate-specific antigen; vs, versus.