Background
Many etiologies exist for microscopic hematuria such as infection, urolithiasis, benign prostate hyperplasia, malignancy, nephropathies or physiologic. About 3.6% of patients presenting with microscopic hematuria will present a urinary tract malignancy [
1] but positive predictive value of microhematuria for malignancy is low and thus population screening has not been recommended [
1‐
3]. The definition of microscopic hematuria is three or greater red-blood cells (RBC) per high power field on a properly collected microscopic urinalysis as per the American Urological Association guidelines [
1] whereas the Canadian Urological Association guidelines require confirmation with a second microscopic urinalysis [
4]. However, in clinical practice, microscopy is often not ordered or not performed by the laboratory. Several studies have confirmed that dipstick urinalysis has good specificity (65–95%) and sensitivity (91–100%) in detecting microhematuria; [
5] rates of false positives and negatives are low and can be due to hemoglobinuria, myoglobinuria, ascorbic acid or reducing agents such as povidone.
Routine screening dipstick urinalysis is currently not recommended by any organization, including the Canadian Task Force on Preventive Health Care, as there is insufficient data to support this type of screening [
6]. However, up to 50% of general practitioners perform a routine urinalysis on all their patients as part of annual health screening visits [
7]. Microscopic hematuria (MH) is a common finding during routine urinalysis and leads to frequent referrals to urologists and nephrologists [
8]. According to current guidelines, MH often prompts a workup of the lower and upper tracts with cystoscopy and abdominal imaging representing a significant cost to health care systems [
4].
Our primary objective was to identify and describe factors associated with microscopic hematuria. We also report on the prevalence of MH in the male population presenting to a men’s health fair.
Methods
Men who presented to an annual McGill University public men’s health fair held in public venues in Montreal, Canada from 2008 to 2013 were included. Informed consents were obtained from all participants to permit anonymous analyses of collected data for educational and academic research purposes. All men who presented to this annual health fair were eligible for inclusion into the study. In addition to physical examination, patients were asked to complete a health questionnaire including socio-demographic data, medical history, medications, lifestyle (smoking, alcohol use and drugs), Metabolic Equivalent of Task scale (METs), Sexual Health Inventory for Men (SHIM), Androgen Deficiency in Aging Male (ADAM), Berlin questionnaire for obstructive sleep apnea (BQ), International Prostate Symptom Score (IPSS) and Overactive Bladder 8 (OAB8). Depending on their age, patients were offered prostate specific antigen (PSA), cholesterol panel and testosterone level testing. They also underwent a digital rectal exam and a dipstick urinalysis.
Patients who stated a previous history of hematuria or did not provide a urine sample were excluded from the final study population. Baseline characteristics were compared using t-tests for continuous variables and chi-square or Fisher exact for categorical variables depending on the number of patients in that particular analysis. Multivariate logistic regression was used to examine various factors and their association with microscopic hematuria and establish the odds-ratio of microhematuria on dipstick urinalysis. Where data was missing, analysis was done only with patients with complete records available. Missing data was primarily due to patients not answering specific questions on the questionnaire. Significant p values were set as two-tailed p < 0.05. Data was analyzed using SPSS version 17.
Results
Data was reviewed on 979 patients who presented to the men’s health fair from 2008 to 2013; 850 provided a urine sample and had no history of previous hematuria and formed the basis of this report. Mean and median age of men was 54.7 and 55 respectively (range 20 to 87). Baseline demographics of the population are presented in Table
1 Mean body-mass index (BMI) was 27.6. Of 850 patients, 67 (7.9%) had diabetes mellitus (DM), 46 (5.4%) had coronary artery disease (CAD), 156 (18.4%) had hypertension (HTN) and 18 (2.1%) had a history of malignancy. From a urological aspect, 42 (4.9%) had a history of previous urological surgery, 42 (4.9%) had a history of urinary or urological infections and 41 (4.8%) had a history of stones.
Table 1
Demographics and comorbidities
Education Level | Grade 7 or lower: 3.1% (26) |
Some high school: 8.9% (76) |
High school graduate or CEGEP: 24.8% (211) |
Some University: 13.1% (111) |
University Graduate: 37.2% (316) |
Post-graduate studies: 11.4% (97) |
Smoking history | Non-smoker: 67.9% (573) |
Smoker: 12.3% (104) |
Ex-smoker: 19.8% (167) |
BMI (kg/m2) | 27.6 ± 5.0 |
Dipstick hematuria | Overall: 73 (8.6%) |
+: 41 (4.8%) |
++: 17 (2%) |
+++: 11 (1.3%) |
++++: 4 (0.5%) |
Proteinuria | 128 (15.1%) |
Diabetes | 67 (7.9%) |
Hypertension | 156 (18.4%) |
Coronary artery disease | 46 (5.4%) |
PSA (ng/mL) | 1.54 ± 1.74 |
Seventy-three (8.6%) patients demonstrated MH. There was no significant difference in rates of coronary artery disease, previous history of urolithiasis, malignancy, urological surgery, urological infections or hypertension between patients with and without MH. Smoking rates (present, past, ever) were similar in both groups (Table
2). Distribution of IPSS score categories was similar between both groups (6.1% vs 6.3% severe scores,
p = 0.825). There was no difference between SHIM score categories (
p = 0.479). On multivariable analysis, the only factors associated with MH were diabetes (OR 2.8,
p = 0.007) and proteinuria (OR 2.9,
p = 0.0001) (Table
3).
Table 2
Comparison of associated factors
Age | 54.7 (+/−12.9) | 55.4 (+/−10.6) | 850 | 0.669 |
Diabetes mellitus | 7.1% (55) | 16.4%(12) | 850 | 0.005 |
Hypertension | 18.3% (142) | 19.2% (14) | 850 | 0.849 |
Coronary artery disease | 5.4% (42) | 5.5% (4) | 850 | 1.000 |
Malignancy | 2.2% (17) | 1.4% (1) | 850 | 1.000 |
Urological surgery | 4.8% (37) | 6.8% (5) | 850 | 0.431 |
History of urolithiasis | 4.8% (37) | 5.5% (4) | 850 | 0.773 |
Urological infections | 5.1% (40) | 2.7% (2) | 850 | 0.571 |
Smoking | 12.4% (96) | 11.3% (8) | 844 | 0.778 |
Proteinuria | 13.4% (104) | 32.9% (24) | 850 | 0.0001 |
IPSS category (mild, mod, severe) | Mild: 58% (407) | Mild: 61.9% (39) | 765 | 0.825 |
Moderate: 35.9% (252) | Moderate: 31.7% (20) |
Severe: 6.1% (43) | Severe: 6.3% (4) |
OAB-q v8 | 39.6% (280) | 34.3% (23) | 774 | 0.434 |
SHIM | No ED: 48% (306) | No ED: 53.2% (33) | 797 | 0.479 |
Mild: 28.7% (183) | Mild: 27.4% (17) |
Mild-Mod: 3.3% (85) | Mild-Mod: 8.1% (5) |
Moderate: 6.1% (39) | Moderate: 9.7% (6) |
Severe: 3.9% (25) | Severe: 1.6% (1) |
ADAM questionnaire positive | 64.4% (482) | 52.9% (37) | 819 | 0.069 |
Metabolic syndrome | 28.5% (142) | 39.4% (13) | 532 | 0.234 |
PSA > 4 ng/ml | 7.3% (47) | 7.5% (5) | 715 | 0.950 |
BMI | < 25: 28.8% (220) | < 25: 26.0% (19) | 837 | 0.688 |
25–30: 45.5% (348) | 25–30: 43.8% (32) |
> 30: 25.7% (196) | > 30: 30.1% (22) |
Table 3
Multivariate logistic regression analysis of factors associated with microhematuria
Diabetes | 2.758 (1.312–5.799) | 0.007 |
Hypertension | 0.775 (0.383–1.568) | 0.478 |
Coronary artery disease | 0.965 (0.318–2.932) | 0.951 |
Smoking | 0.934 (0.427–2.045) | 0.864 |
Proteinuria | 2.882 (1.669–4.976) | 0.0001 |
BMI ≥ 30 | 1.015 (0.966–1.068) | 0.551 |
Age | 0.998 (0.977–1.020) | 0.857 |
Conclusion
The prevalence of microhematuria in the general male population presenting to a public health fair was 8.6%, in keeping with other reported studies of prevalence of MH. Significant factors associated with MH were a history of diabetes and concomitant proteinuria.
Acknowledgements
Not applicable.
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