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Keywords:

  • erectile dysfunction;
  • diabetes mellitus;
  • fasting glucose;
  • urinary dipstick testing;
  • screening;
  • prevalence

Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. Authors

Objective To determine the prevalence of previously undiagnosed diabetes mellitus (DM) in men presenting with erectile dysfunction (ED), using fasting blood glucose (FBG) compared with urinary dipstick testing for glycosuria.

Patients and methods A prospective prevalence study was carried out in an andrology outpatient clinic of a urology department in a district general hospital serving a mixed urban and rural population. In all, 129 consecutive men presenting with ED underwent FBG and urinary dipstick testing to detect undiagnosed DM in those presenting with ED.

Results The prevalence of known DM was 17% and the that of undiagnosed DM 4.7% of the 107 remaining men; an abnormal fasting glucose level was found in a further 12%. The sensitivity of urine dipstick test for diagnosing DM was 20%.

Conclusions The prevalence of undiagnosed DM is higher in men with ED than in the general population. ED is a marker symptom for DM and DM should be actively sought in men presenting with ED. Urinary dipstick testing for glycosuria, if used as a screening test, will miss the diagnosis in 80% of these men. FBG testing should be undertaken to reliably diagnose DM in men presenting with ED.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. Authors

Erectile dysfunction (ED) is considered as a marker symptom for as yet undiagnosed diabetes mellitus (DM) [1] and is associated with cardiovascular diseases [2]. DM can be diagnosed early in the course of the disease by appropriate testing. People with diabetes are at increased risk of peripheral vascular, cerebrovascular and ischaemic heart disease. Early diagnosis may prevent and/or delay serious complications [3].

Screening for DM using tests for glycosuria is highly specific, but has poor sensitivity and is not recommended for population screening for Type 2 (non-insulin dependent) DM [4]. Diabetes UK (formerly the British Diabetic Association, BDA) recommends testing the fasting blood glucose (FBG) level to reliably diagnose DM. Random blood glucose level in the presence of symptoms and the oral glucose tolerance test (OGTT) are two other methods used in the diagnosis, although the latter is not recommended for routine clinical use [5].

There are suggestions that diabetes be actively sought in men with ED [6]; there is no consensus amongst those managing such men in the UK on which test to use to diagnose diabetes [7,8]. The purpose of the present study was to determine the prevalence of undiagnosed DM and to evaluate the effectiveness of FBG compared with urinary dipstick testing as a means of diagnosing diabetes in men referred to the andrology outpatient clinic with ED.

Patients and methods

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. Authors

In a prospective study, 129 consecutive men with ED were seen at our hospital by a urologist during an 8-month period (October 1999 to May 2000). All of them had a sample of their urine tested during their initial visit by an experienced nurse using a standard reagent strip (Multistix SG™, Bayer Diagnostics, UK), according to the instructions in the manual. Twenty-two patients (17%) were already known to have DM; the remainder (107) were then asked to fast overnight (at least an 8 h calorie-free period) and blood taken for FBG testing in the hospital pathology laboratory. All patients had their blood taken within 2 weeks of the initial visit. The FBG test in our institution measures venous plasma values; the samples were analysed using the Vitros GLU Slides (Vitros Chemical Products, Ortho-Clinical Diagnostics, Amersham, Bucks, UK), colorimetric assay based on glucose oxidase and peroxidase.

DM was diagnosed if the FBG was geqslant R: gt-or-equal, slanted 7.0 mmol/L (according to the WHO diagnostic criteria for a venous plasma sample, endorsed by Diabetes UK and effective in the UK from 1 June 2000 [9]). Men with a new diagnosis of DM were contacted by telephone and follow-up management arranged with the GP, which included repeat measurement of FBG to confirm the diagnosis.

Men with a FBG of geqslant R: gt-or-equal, slanted 6.1 but < 7.0 mmol/L were considered to have impaired fasting glucose (IFG). Men with a FBG of > 5.5 (the upper limit of the normal range provided by our laboratory) but  < 6.1 mmol/L were considered to have abnormal FBG. These two groups of men were advised to undergo repeat testing by their GP 6 months later and GPs were informed of the need for surveillance in these patients. For the purposes of this study these two groups were combined as having an ‘abnormal FBG’. These ‘at risk’ patients, who may have either impaired glucose tolerance (IGT) or impaired fasting glycaemia, were also informed about associated risk factors (obesity, family history of DM, Asian/African racial origin) [10], if present, and the benefits of regular physical exercise, weight loss, stopping smoking and a healthy diet.

The variables were not normally distributed and hence nonparametric statistical methods were used, e.g. the binomial test for proportions, the Mann–Whitney U-test for comparing two groups and Spearman's rho test for correlation between the variables (with correlations deemed significant at Pleqslant R: less-than-or-eq, slant 0.05).

Results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. Authors

The results of screening are shown in Table 1. Patients were categorized into the following three groups: group 1, patients with newly diagnosed DM; group 2, patients with IFG levels and abnormal FBG; group 3, patients with a normal FBG. All men with abnormal results in this study were Caucasians. There was no statistically significant difference in age between those with normal and abnormal FBG; Fig. 1 shows the increasing trend in the median duration of ED in the groups. The duration of ED was significantly longer in group 1 than in group 3 (Mann–Whitney U-test, P = 0.04).

Table 1.  Patient characteristics and results of screening using FBG (all values refer to venous plasma levels).
CharacteristicMen with ED (129)
Median (range) age (years)58 (36–73)
Race, n (%)
Caucasian119 (92)
Black5 (4)
Asian5 (4)
Known diabetics, n (%)22 (17)
New diagnosis of DM (% of 107 men)5 (5)
Abnormal FBG (including IFG)13 (12)
image

Figure 1. Box-plots of duration of ED by FBG diagnostic groups. In each group the green box shows the 25–75th percentile, the red line the median and the light green bars the 95% CI. There was a statistical difference only between Group 1 and Group 3. The light red symbols show the close (circles) and extreme (squares) outliers.

Download figure to PowerPoint

Glycosuria on dipstick testing was present in only one of the five newly diagnosed diabetic patients (Table 2). Otherwise, dipstick testing did not identify any other ‘at risk’ patients. Thus, the sensitivity of dipstick glycosuria for diagnosing DM in this series was only 20%, while the specificity was 100%.

Table 2.  Results of dipstick testing for glycosuria
GroupDipstick + veDipstick –veTotal
1145
201313
308989
Total1106107

Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. Authors

The prevalence of ED in diabetic men has been examined extensively but there have been few studies assessing the incidence of undiagnosed DM in men with ED. In the UK, Gatling et al.[11] found a prevalence of known diabetes of 1.01% in a typical English community of 90 660 people; 74% of the diabetics identified were of Type II. In the Islington Diabetes Survey the prevalence of undiagnosed diabetes in men age > 40 years was 1.06% (11 in 1040) [12]; ED occurs at an earlier age and more frequently in diabetic men, and is considered a marker symptom for DM [13].

In the present study, the prevalence of undiagnosed DM was 4.7% in an unselected population of men from Southern England presenting with ED. In addition, another 3.7% had an abnormal FBG, suggesting either IGT or IFG, which are not clinical entities in their own right, but are categories ‘at risk’ for future diabetes and/or cardiovascular disease [14]. Abnormal blood glucose levels based on the range provided by the laboratory was found in 8.4% of men and this group may require surveillance, especially those with additional risk factors [10].

In the only other similar study, Deutsch and Sherman [1], using the OGTT, reported a 12.1% prevalence (58 men) of as yet undiagnosed DM in impotent men, compared with none in those with premature ejaculation (69 men) or normal sexual function (63 men), despite a lower mean age in the impotent group in their study (47.2 years). The higher prevalence rate in their study may have arisen because they used the OGTT, which is a more sensitive and specific screening test than FBG [10], and regarded as the ‘gold standard’ for screening for DM, although it is less practical and is not recommended for routine clinical use [5].

The BDA recommends considering diabetes as the underlying diagnosis in patients with hypertension, ischaemic heart disease, peripheral vascular disease and cerebrovascular disease [5]. The Massachusetts Male Aging Study showed a clear significant correlation between ED and heart disease and two associated risk factors, hypertension and low serum high-density lipoprotein [2]. We contend that men with ED are a high-risk group and hence DM should be actively sought in these men. Currently we suspect that such men are not undergoing FBG testing and there is an undue reliance on dipstick testing for glycosuria or random blood glucose testing. The BDA, through its Professional Advisory Committee, recommends the use of either fasting plasma glucose or postprandial glycosuria as a screening tool in asymptomatic individuals. When used as screening tests, glycosuria and random blood sugar levels perform very poorly [4,10]. If the dipstick test of urine alone had been used in the present men it would have missed four of the five new cases of DM. Moreover, none of the patients with abnormal glycaemia had glycosuria on dipstick testing.

Type 2 DM goes undiagnosed for many years and such patients are at increased risk of developing microvascular (e.g. retinopathy) and macrovascular complications (significantly increased risk for coronary heart disease, stroke and peripheral vascular disease) [14–16]. The duration of ED in the present men was significantly longer in the newly diagnosed diabetics than in those with normal FBG values, although there could be other confounding variables to explain this finding. Early detection and treatment, and the opportunity to alter lifestyle, may reduce the long-term morbidity of Type 2 DM [15]. Adequate glycaemic control reduces the risk of complications [3]. A further incentive for diagnosing and treating DM in the ED population is that glycaemic control, measured using haemoglobin A1c, predicts erectile function [17], although it is not yet established if improved glycaemic control leads to improved erectile function. The first presentation of a man with ED is the ideal time to exclude DM by FBG testing.

There is currently a trend to shift the management of ED to primary care. As the burden of initial management of these diabetics rests on GPs, ideally men with ED should have their FBG assessed by the GP before referral to specialists. In the case of nurse-led ED clinics, FBG testing should be incorporated into the management protocol. The cost of active case-finding in high-risk groups is likely to be less than that of caring for a more advanced diabetic patient. In this study five diabetics were identified at an extra cost of £38.52 each (107 patients at a FBG test cost of £1.80) (OmniLabs UK Ltd, Lister Hospital, contract price, 2000).

In conclusion, ED is a marker symptom for DM and hence all men presenting with ED should have their FBG tested; this has resource implications. Urinary dipstick testing can supplement this to identify other problems, but is not a useful screening test for diabetes.

Acknowledgements

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. Authors

We are grateful to Pfizer plc for providing an independent educational grant towards the Research Fellowship of K.S. Pfizer plc have neither contributed nor influenced the material data or conclusions of this study. We are grateful to Dr L. Borthwick, Consultant Diabetologist and Physician, Lister Hospital, Stevenage, for his expert comments on the diabetic aspects of this paper.

References

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Authors

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. Authors

K. Sairam, FRCS, DipUrol, Research Fellow in Urology.

E. Kulinskaya, PhD(Stats), MSc(Maths), Senior Statistician.

G.B. Boustead, FRCS(Urol), Consultant Urologist.

D.C. Hanbury, MS, FRCS(Urol), Consultant Urologist.

T.A. McNicholas, FRCS(Urol), FEBU, Consultant Urologist.

Abbreviations
ED

erectile dysfunction

DM

diabetes mellitus

BDA

British Diabetic Association

FBG

fasting blood glucose

OGTT

oral glucose tolerance test

IFG

impaired fasting glucose

IGT

impaired glucose tolerance.