A Systematic Review Assessing the Economic Impact of Sildenafil Citrate (Viagra®) in the Treatment of Erectile Dysfunction

The Effect of Phosphodiesterase-type 5 Inhibitors on Erectile Function: An Overview of Systematic Reviews

Background: Multiple systematic reviews explore the effect of phosphodiesterase type 5 (PDE5) inhibitors on erectile dysfunction (ED), with each study addressing specific outcomes. However, physicians and policymakers require a holistic approach of this topic.

Objective: To summarize the current evidence regarding the efficacy and safety of PDE5 inhibitors for the management of ED through an overview of systematic reviews.

Methods: Studies were identified by searching PubMed, Web of Science, Cochrane Library and Scopus databases, as well as sources of grey literature until June 12, 2021 (PROSPERO: CRD42020216754). We considered systematic reviews, meta-analyses or network meta-analyses of randomized trials that provided outcomes about the efficacy and safety of any approved PDE5 inhibitor (avanafil, sildenafil, tadalafil and vardenafil). We constructed forest plots for meta-analytic effects regarding the change in erectile function, adverse events and dropouts after administration of PDE5 inhibitors in the general population and in specific patient groups.

Results: We included 23 studies with 154,796 participants and a total of 258 meta-analytic effects. Sildenafil 25 mg [Weighted Mean Difference (WMD): 13.08, 95% Confidence Interval (CI): 10.1-16.06] seemed to be statistically superior to all interventions in improving erectile function compared to placebo, but studies with low-dose sildenafil are lacking. Moreover, comparing among different PDE5 inhibitors, sildenafil 50 mg or sildenafil 100 mg were considered the most effective compounds in the general population. The latter derived, however, predominantly from indirect comparisons among different PDE5 inhibitors. Still, sildenafil 100 mg was associated with more treatment-related adverse events and dropouts. Interestingly, low-dose daily tadalafil may be more effective than high-dose on-demand tadalafil (WMD: 1.24, 95% CI: 0.03-2.44). Furthermore, testosterone and PDE5 inhibitors in patients with ED and hypogonadism seem to further improve symptoms, while the addition of a-blockers in patients with urinary symptoms treated with PDE5 inhibitors does not provide additional benefits (WMD: −0.8, 95% CI: −1.65-0.06).

Conclusion: Although the efficacy and safety of PDE5 inhibitors, compared to placebo, is well-documented, the existing evidence comparing different PDE5 inhibitors is low. Therefore, high-quality, head-to-head, trials comparing different PDE5 inhibitors are necessary to determine their ideal dosage and formulation based on their safety and efficacy profile.

Systematic Review Registration: PROSPERO, identifier [CRD42020216754].

Increasing access to erectile dysfunction treatment via pharmacies to improve healthcare provider visits and quality of life: Results from a prospective real-world observational study in the United Kingdom

OBJECTIVES

The Medicines and Healthcare Products Regulatory Agency in the United Kingdom (UK) formally reclassified sildenafil citrate 50 mg tablets as a pharmacy medicine (sildenafil-P) in 2017 for adult men with erectile dysfunction (ED). A 1-year prospective real-world observational study was conducted to track men's health behaviour, particularly their healthcare resource utilisation (HCRU) and quality of life (QoL) before and after the availability of sildenafil-P.

METHODS

Adult men with ED aged ≥18 years provided data at baseline (prior to launch of sildenafil-P) and every 3 months after the launch. Demographics, health characteristics, treatments at baseline and HCRU, including number of pharmacist and physician/nurse practitioner visits over time are reported. QoL-related outcomes were assessed via the Self-Esteem and Relationship Questionnaire (SEAR), 2-Item Patient Health Questionnaire and ratings of sexual satisfaction. Generalised linear models were used to assess the association of sildenafil-P use with total physician/nurse practitioner and pharmacist visits and QoL-related outcomes at 12 months.

RESULTS

Overall, 1162 men completed the survey at all 5 time points. The mean ± SD age was 59.02 ± 12.06 years; 55.42% reported having a moderate-to-severe ED. Hypertension (37.52%) and hypercholesterolaemia (31.50%) were the most common risk factors for ED. At baseline, 62.99% were not using any ED treatment. After adjusting for baseline visits/other covariates, mean physician/nurse practitioner (3.68 vs 2.87; P = .003) and pharmacist visits for any reason (2.10 vs 1.34; P < .001) at 12 months were significantly higher among sildenafil-P users than those who never used sildenafil-P. Sildenafil-P users also had significantly higher SEAR total and domain (sexual relationship and self-esteem) scores at 12 months.

CONCLUSION

Following the reclassification to a pharmacy medicine in the UK, sildenafil-P was associated with a higher number of physician/nurse practitioner and pharmacist visits for any reason. Sildenafil-P use was also associated with better QoL, although group differences were small in magnitude.

Role of application of tadalafil 5 mg once-daily (≥6 months) in men with erectile dysfunction from six randomized controlled trials

This meta-analysis was performed to assess the efficacy and safety of taking tadalafil 5 mg once-daily for at least 6 months in the treatment of erectile dysfunction (ED). Based on databases: MEDLINE, EMBASE and Cochrane Controlled Trials Register, this analysis was performed to collect randomized controlled trials (RCTs) of tadalafil 5mg once-daily in treating ED over 6 months. Reviewers also investigated the references of each literature. The meta-analysis covered a total of 1,596 patients in six RCTs. The tadalafil group performed a better effect in terms of the international index of erectile function-erectile function (IIEF) domain (P=0.005) for the treatment of ED compared with the placebo group. Safety assessments including discontinuations due to adverse events (AEs) (P=0.31) and treatment-emergent AEs (P=0.06) indicated that the tadalafil group had a better tolerate. The analysis elucidates that the dose of 5 mg per day of tadalafil showed a good effect after the treatment of at least 6 months relative to the control group with fewer side effects.

Erectile dysfunction management after failed phosphodiesterase-5-inhibitor trial: a cost-effectiveness analysis

BACKGROUND

To evaluate the cost-effectiveness of alternate erectile dysfunction (ED) management options after failed first line phosphodiesterase-5-inhibitors (PDE5-I).

METHODS

An empiric, repetitive decision tree analysis model was constructed using literature review and expert clinical judgement. This assessed the expected costs and quality adjusted life years (QALYs) of decision alternatives over a 10-year period. The model incorporated interventions including alternate PDE5-Is, intracorporal injections (ICI) with alprostadil or trimix (alprostadil, phentolamine, and papaverine), and inflatable penile prosthesis placement (IPP) and included respective risks of failure, subsequent interventions, and other complications (including priapism risk). Average model QALY estimates obtained from the literature were as follows: ED =0.56, successful alternate PDE5-I =0.70, successful ICI =0.70, and successful IPP =0.78. Cost data were calculated from a high-volume academic center and published manufacturer data.

RESULTS

Over the 10-year period, IPP placement was the most cost-effective management option per preserved QALY (QALY =7.82, cost =$22,009/10 years) as compared to ICI alprostadil (QALY =8.51, cost =$62,890/10 years), ICI trimix (QALY =8.47, cost =$48,617/10 years) and alternate PDE5-I (QALY =7.73, $52,883/10 years).

CONCLUSIONS

Using expert opinion and published utility, cost, and complication data in a decision analysis, we demonstrated that IPP placement is the most cost-effective ED intervention following failed initial PDE5-I over a 10-year period as compared to alternate treatment options. Such cost-effectiveness outcomes may be used in ED management counseling.

The pharmacist's role in improving the treatment of erectile dysfunction and its underlying causes

Erectile dysfunction (ED), which worldwide is likely to affect in excess of 300 million men by 2025, is often either untreated or insufficiently treated. It can be a prelude to other serious illnesses and may be a cause or consequence of depression in affected individuals. Among men younger than 60 years of age, ED can be a robust early-stage indicator of vascular disease and type 2 diabetes. Untreated or inadequately treated ED can also be a sign of poor communication between health professionals and service users of all ages. Improved treatment of ED could cost-effectively prevent premature deaths and avoidable morbidity. The extension of community pharmacy‒based health care would enable more men living with ED to safely access effective medications, along with appropriate diagnostic services and support for beneficial lifestyle changes such as smoking cessation in conveniently accessible settings. The task of introducing improved methods of affordably addressing problems linked to ED exemplifies the strategic challenges now facing health care systems globally. Promoting professionally supported self-care in pharmacies has the potential to meet the needs of aging populations in progressively more effective ways.

A state-of-art review of low intensity extracorporeal shock wave therapy and lithotripter machines for the treatment of erectile dysfunction

INTRODUCTION

Current treatment for erectile dysfunction (ED) mostly attempts to improve erectile function with limited impact on altering the underlying pathophysiology of ED. Recent animal experiments have supported the notion that low intensity extracorporeal shockwave therapy (LIESWT) significantly improves penile hemodynamics and might induce structural changes that regenerate penile tissue. Areas covered: This review article provides an overview of the basic mechanics and clinical studies pertaining to LIESWT and its use in the field of ED. We identify several key aspects of LIESWT and compare contemporary LIESWT machines and their clinical outcomes. Expert commentary: There is emerging and strong literature to support the use of LIESWT in men with ED, with many clinical studies reported encouraging results in the use of LIESWT with improved erectile function, good safety records, and short-term durability. However, there is a need to define which subgroup of ED population is best suited and the LIESWT treatment protocol including LIESWT template, modality of shock waves energy, emission frequency, and total energy delivery. More stringent randomised controlled trials are warranted before there is widespread acceptance of this LIESWT technology as the standard of care in ED.

Association between coronary heart disease and erectile dysfunction in Chinese Han population

To investigate the association between coronary heart disease (CHD) and erectile dysfunction (ED) in Chinese Han population. Patients who went to the andrological out-patient clinic of our hospital between August 1, 2015 and May 1, 2016 and met all eligible criteria were enrolled in this study. The patients diagnosed as ED using self-administered International Index of Erectile Function-5 (IIEF-5) questionnaire were considered as case group and others were considered as control. The cases were categorized as mild, moderate, and severe ED. Subjects were interviewed for the history of CHD. Uni- and multivariate logistic regression models were used to calculate odds ratios (ORs) and corresponding 95% confidence intervals (CIs) using the SPSS 18.0 software. A total of 240 participants (56 ED patients and 184 controls) were enrolled. CHD prevalence was higher in cases without statistical significance (OR = 1.20, 95%CI = 0.63-2.29; p = 0.58). Results of adjusted analysis also showed a non-significantly increased risk (OR = 1.25, 95%CI = 0.55-2.85; p = 0.59). Stratified analysis by severity of ED revealed similar results. This study suggests no significant association exists between CHD and ED in Chinese Han population.

Implanted Muscle-Derived Stem Cells Ameliorate Erectile Dysfunction in a Rat Model of Type 2 Diabetes, but Their Repair Capacity Is Impaired by Their Prior Exposure to the Diabetic Milieu

INTRODUCTION

Muscle-derived stem cells (MDSCs) and other SCs implanted into the penile corpora cavernosa ameliorate erectile dysfunction in type 1 diabetic rat models by replenishing lost corporal smooth muscle cells (SMCs) and decreasing fibrosis. However, there are no conclusive data from models of type 2 diabetes (T2D) and obesity.

AIM

To determine whether MDSCs from obese Zucker (OZ) rats with T2D at an early stage of diabetes (early diabetic SCs isolated and cultured in low-glucose medium [ED-SCs]) counteract corporal veno-occlusive dysfunction and corporal SMC loss or lipo-fibrosis when implanted in OZ rats at a late stage of diabetes and whether MDSCs from these OZ rats with late diabetes (late diabetic SCs isolated and cultured in high-glucose medium [LD-SC]) differ from ED-SCs in gene transcriptional phenotype and repair capacity.

METHODS

ED-SCs and LD-SCs were compared by DNA microarray assays, and ED-SCs were incubated in vitro under high-glucose conditions (ED-HG-SC). These three MDSC types were injected into the corpora cavernosa of OZ rats with late diabetes (OZ/ED, OZ/LD, and OZ/ED-HG rats, respectively). Untreated OZ and non-diabetic lean Zucker rats functioned as controls. Two months later, rats were subjected to cavernosometry and the penile shaft and corporal tissues were subjected to histopathology and DNA microarray assays.

MAIN OUTCOME MEASURES

In vivo erectile dysfunction assessment by Dynamic Infusion Cavernosometry followed by histopathology marker analysis of the penile tissues.

RESULTS

Implanted ED-SCs and ED-HG-SCs improved corporal veno-occlusive dysfunction, counteracted corporal decreases in the ratio of SMCs to collagen and fat infiltration in rats with long-term T2D, and upregulated neuronal and endothelial nitric oxide. LD-SCs acquired an inflammatory, pro-fibrotic, oxidative, and dyslipidemic transcriptional phenotype and failed to repair the corporal tissue.

CONCLUSION

MDSCs from pre-diabetic rats injected into the corpora cavernosa of rats with long-term T2D improve corporal veno-occlusive dysfunction and the underlying histopathology. In contrast, MDSCs from rats with long-term uncontrolled T2D are imprinted by the hyperglycemic and dyslipidemic milieu with a noxious phenotype associated with an impaired tissue repair capacity. SCs affected by diabetes could lack tissue repair efficacy as autografts and should be reprogrammed in vitro or substituted by SCs from allogenic non-diabetic sources.

Tadalafil 5 mg Once Daily Improves Lower Urinary Tract Symptoms and Erectile Dysfunction: A Systematic Review and Meta-analysis

OBJECTIVES

We carried out a systematic review and meta-analysis to assess tadalafil 5 mg once-daily for the treatment of lower urinary tract symptoms (LUTS) and erectile dysfunction (ED).

METHODS

A literature review was performed to identify all published randomized double-blind, placebo-controlled trials of tadalafil 5 mg once-daily for the treatment of LUTS and ED. The search included the following databases: MEDLINE, EMBASE, and the Cochrane Controlled Trials Register. The reference lists of the retrieved studies were also investigated.

RESULTS

Thirteen publications involving a total of 3973 patients were used in the analysis, including 13 RCTs that compared tadalafil 5 mg once-daily with placebo. We found that tadalafil 5 mg once-daily was effective in improving LUTS suggestive of BPH and treating ED over 12 weeks in our meta-analysis. Total International Prostate Symptom Score (IPSS) (SMD = - 2.02, 95% CI = - 2.52 to -1.53, P < 0.00001); Benign Prostatic Hyperplasia Impact Index (BPH-II) (SMD = -0.58, 95% CI = -0.84 to -0.33, P < 0.00001); International Index of Erectile Function-erectile function (IIEF) domain (standardized mean difference [SMD] = 5.18, 95% confidence interval [CI] = 4.13-6.23, P < 0.00001) indicated that tadalafil 5 mg once-daily was more effective than the placebo. Safety assessments included discontinuations due to adverse event (odds ratio (OR) = 1.79, 95% CI = 1.12-2.85, P = 0.01) indicated that tadalafil 5 mg once-daily was well tolerated.

CONCLUSIONS

This meta-analysis indicates that tadalafil 5 mg once-daily to be an effective treatment for LUTS and ED with a low occurrence of side effects.

Efficacy and safety of phosphodieterase-5 inhibitors for treatment of erectile dysfunction secondary to spinal cord injury: a systemic review and meta-analysis

STUDY DESIGN

Systemic reviewObjective:We carried out a systematic review and meta-analysis to assess the efficacy and safety of phosphodieterase-5 (PDE5) inhibitors on erectile dysfunction (ED) secondary to spinal cord injury (SCI).

METHODS

A literature review was performed to identify all published randomized, double-blind, placebo-controlled trials of PDE5 inhibitors for treatment of ED secondary to SCI. The search included the following database: MEDLINE, EMBASE and the Cochrane Library. The outcomes and complications analyzed involved the Global Efficacy Question (GEQ), sexual encounter profile diary question 2 and 3 (SEP2 and SEP3) and adverse events. All statistical analysis was performed using Stata 12.0 software (Stata Corp., College Station, TX, USA).

RESULTS

Six publications were used in analysis, including six randomized controlled trials that compared PDE5 inhibitors with placebo. Compared with placebo, PDE5 inhibitors were associated with significant improvements in GEQ (OR 11.997, 95% CI 8.073-17.830, P<0.0001), SEP2 (RR 1.847, 95% CI 1.561-2.185, P<0.0001) and SEP3 (RR 2.738, 95% CI 2.084-3.598, P<0.0001). Despite significant greater incidences of some adverse events observed (headache: RR 3.717, 95% CI 2.309-5.982, P<0.0001; flushing: RR 9.281, 95% CI 2.858-30.147, P<0.0001; gastrointestinal discomfort: RR 9.064, 95% CI 2.116-38.827, P=0.003), most adverse events were mild to moderate and transient.

CONCLUSIONS

This systematic review and meta-analysis indicate that PDE5 inhibitors are effective and well tolerated to treat ED secondary to SCI compared with placebo, as measured by response to GEQ, SEP2, SEP3 and incidence of adverse events. PDE5 inhibitors could be considered as the first choice in the treatment of ED patients with SCI.

Management of ED under the "severe distress" criteria in the NHS: a real-life study

INTRODUCTION

The United Kingdom is unusual in that a significant proportion of patients with erectile dysfunction (ED) have their treatment fully reimbursed by the National Health Service (NHS). This may have consequences for the choice of treatment and for compliance with treatment.

AIMS

The aim of this study was to evaluate the use and cost implications of phosphodiesterase type 5 inhibitor in an NHS setting.

METHODS

Basic demographics and data on ED management for patients treated from January 2000 to April 2011 were obtained from a prospectively accrued database. We reviewed drug usage and costs as well as switching between drugs. Patients were given the choice of all available therapies and were followed up annually.

MAIN OUTCOME MEASURES

Switching, compliance, and costs of treating ED under the "severe distress" criteria in the NHS were reviewed for this study.

RESULTS

Two thousand one hundred fifty-nine patients qualified for reimbursed therapy. Two hundred twenty-six patients were excluded from further analysis owing to missing data. Patients were followed up on an annual basis. The mean patient age was 60.2 years (min 23, max 90), and the mean follow-up was 50.8 months (min 1, max 127). Six hundred ninety-six were started on sildenafil, 990 on tadalafil, 163 on vardenafil, and 84 on intracavernosal alprostadil. Eighteen percent of patients initially started on the scheme and stopped medication unilaterally. Of the patients, 12.3% changed their medication during follow-up. The cost of drugs increased year by year from £257,100 in 2007 to £352,519 in 2011.

CONCLUSIONS

Our real-life observational study shows that in our institution, dropout of therapy is unusual. We hypothesize that this reflects, in part, the reimbursement issue. We also found that switching between drugs was unusual, although there are several possible explanations for that. Although this is a successful system for the patients, the hospital, which bears the costs of medication, is finding this an increasing economic drain.