Temporal Trends in Intracavernosal Injection Therapy and Penile Prosthesis Implantation in the Era of Phosphodiesterase‐5 Inhibitors for Erectile Dysfunction in Australia

ABSTRACT

Introduction

Phosphodiesterase‐5 inhibitors (PDE5‐Is) transformed erectile dysfunction (ED) management as first‐line therapy; nonetheless, many patients require second‐ and third‐line options due to inadequate response, side effects, or contraindications. This article evaluates temporal trends in intracavernosal injection (ICI) therapy and penile prosthesis implantation (PPI) in Australia since PDE5‐Is introduction.

Methods

MBS item numbers 37415 (ICI), and 37429/37426 (PPI) from 1998 to 2024 were analysed. Data were stratified by age and state, standardised to Australian male population estimates, and reported per 100 000 men. Compound annual growth rates (CAGR) were calculated with break points at major events (release of PDE5‐Is, generics, COVID‐19). RPBS data were extracted for eligible PDE5‐Is and alprostadil from 1998 to 2024. Government expenditure was included and trends compared with international cohorts.

Results

Across 260 756 procedures (17 882 PPI; 242 874 ICI), PPI sharply declined in 1996–1999 (CAGR −16.02%/year) after sildenafil introduction but demonstrated sustained growth over time (+7.08%/year 2000–2009 and +4.73%/year 2010–2020). Growth slowed to +1.94%/year 2020–2024 with COVID‐related elective surgery disruptions. ICI use collapsed after 1998, stabilised in the 2010s, and contracted further during COVID, equating to a 97% reduction (CAGR −11.4%/year). PPI shifted toward older men aged 55–84 with marked increase in those aged 65–74 and 75–84 years, while ICI has transitioned to almost exclusive use in men over 55 years old. Government expenditure declined more than sixfold between 1996 and 2003 but plateaued since 2010 with PPI and ICI maintaining similar annual cost. From 1999 to 2024, RPBS‐subsidised PDE5‐Is prescriptions rose from ~440 to 25 500 yearly prescriptions, with early sildenafil predominance shifting to tadalafil, which accounts for 58% of use in 2024.

Conclusion

There has been a considerable change in trends of invasive ED therapies over the past 30 years since the introduction of PDE5‐Is. There has been a significant decline in ICI therapy over the study period, with a recent increased uptake in PPI utilisation.

1. Introduction

Erectile dysfunction (ED) is a highly prevalent condition that can have a significant impact on both patients and their partners [1, 2]. It is defined as the persistent or recurrent inability to achieve a penile erection sufficient for sexual performance or satisfaction [3, 4]. Although ED is not limited to older men, incidence increases with age and in the presence of comorbidities such as obesity, diabetes and vascular disease [5, 6]. ED is often under‐reported, and as a result, under‐treated globally, with embarrassment and taboo acting as barriers to seeking treatment [7].

The therapeutic landscape for ED has changed dramatically over the past 25 years. Since the late 1990s, oral phosphodiesterase 5 inhibitors (PDE5‐Is) have been established as first‐line treatment in most international guidelines [8, 9, 10, 11]. PDE5‐Is work by preventing cyclic guanosine monophosphate (cGMP) degradation, resulting in cavernous vasodilation and penile tumescence [12]. While there are many PDE5‐Is approved for use in Australia, these medications require a formal prescription and remain largely unsubsidised, potentially creating additional barriers for patients.

Despite their efficacy, 30%–35% of patients fail to respond to PDE5‐I treatment [13], and will require consideration of second‐ and third‐line treatment options such as intracavernosal injections (ICI) and penile prosthesis insertion (PPI). These rates are higher in men with advanced and complex ED, such as following pelvic surgery, including radical prostatectomy, cystectomy or pelvic radiation therapy [14]. These treatments are at least in part subsidised by the Medicare Benefits Schedule (MBS), offering an opportunity to study population‐level utilisation and temporal trends.

International registry and claims data provide an insight into temporal shifts in invasive ED treatment. Medicare data from the United States shows declining rates of ICI use since the introduction of PDE5‐Is and variable rates of penile prosthesis [15, 16]. Similar trends have been demonstrated in Europe and Asia [17, 18]. More recently, international data have demonstrated an uptake in PPI utilisation, which may be related to an increased pool of men with complex ED [19]. Presently, there is limited national‐level data regarding temporal trends in invasive ED treatments in Australia.

An analysis of long‐term, population‐adjusted trends is therefore needed to appreciate how various ED treatments are being employed in Australia. The availability of 30 years of MBS data provides a unique opportunity to investigate these trends using age‐stratified, population‐adjusted statistics. The collection of Medicare rebate data allows for assessment from a health economics perspective in addition to clinical utilisation. This study aims to analyse 30‐year national trends in ED therapies in Australia, with cost and demographic stratification, and compare with published international data. Moreover, this study aims to investigate the impact of several key events in the history of ED management in Australia.

2. Materials and Methods

2.1. Data Source

The MBS is the publicly available list of medical services subsidised by the Australian Government. For each item, the number of services stratified by age and associated government benefits are reported. These data represent subsidised claims processed nationally in private hospitals and private patient encounters in public hospitals. As such, total national activity is underestimated, with services provided entirely within the public system without MBS billing being missed. The Repatriation Pharmaceutical Benefits Scheme (RPBS) is a government program subsidising the cost of medications for eligible veterans, which provides publicly available data stratified by year and state. In Australia, PDE5‐I and alprostadil are the only ED medications subsidised through this program, meaning national utilisation outside the veteran population will not be captured. As the data collected is publicly available, no ethics approval was required for this study.

2.2. Data Collection

MBS item reports were accessed in August 2025 from January 1996 to December 2024. Yearly utilisation data were extracted and stratified by age group and state of provision. This study was designed to capture men initiating invasive therapy for ED. As such, for PPI, revision and replacement procedures were excluded to avoid double‐counting established patients, and for ICI, only in‐office item numbers were included. First‐dose administration is typically performed under supervision per guideline recommendations, while ongoing home administration is not MBS‐rebated and thus not captured.

The following item numbers relating to invasive ED treatment were included:

• Item 37415: Procedure involving injection into the penis to understand and treat problems with erection (impotence).

• Item 37429: Artificial erection device, insertion of pump and pressure‐regulating reservoir.

• Item 37426: Artificial erection device, insertion of into one or both corpora.

Item 37415 includes patients undergoing diagnostic testing, such as penile duplex ultrasonography; this may overestimate total utilisation.

To account for changes in the Australian male population over time, annual utilisation was age‐standardised per 100 000 men at both national and state levels using Australian Demographic Data published by the Australian Bureau of Statistics (ABS). State‐level stratification differed by procedure type due to volume distribution. ICI utilisation was analysed across all eight states/territories. In contrast, PPI procedures were concentrated within higher‐population states; therefore, analyses were restricted to five states with the highest procedural volume to ensure stability of estimates and avoid reporting small cell counts.

RPBS item reports for all subsidised PDE5‐Is (sildenafil, tadalafil, avanafil) and alprostadil were similarly accessed in August 2025 from January 1996 to December 2024. Age stratification is not available for RPBS data, and as such, no age stratification was performed.

2.3. Statistical Analysis

Data was collected and analysed in Microsoft Excel. Utilisation rates were stratified by year, state of provision, and age decade where available.

Compound Annual Growth Rate (CAGR) was used as the primary summary measure of utilisation trends. CAGR provides a standardised estimate of proportional change over a defined interval and facilitates comparison across therapies with different baseline volumes. Era boundaries were predefined to reflect clinically meaningful phases in ED management, including early uptake of oral therapies, maturation and generic availability, and post‐COVID‐19 era.

• 1996–1999 (pre‐PDE5‐I era)

• 2000–2009 (early PDE5‐I era)

• 2010–2019 (maturation and generics era)

• 2020–2024 (contemporary practice and post‐COVID‐19 era)

Government expenditure was derived from the Medicare benefit paid for each item number, which is provided within Medicare item reports. These figures represent only the Medicare subsidy, and exclude items such as device and medication cost, surgical fees or hospital stay and therefore underestimates the total cost to the patient and health system.

Items 37429 and 37426 are typically billed together for inflatable prosthesis insertion, while malleable prostheses use only item 37426. To avoid double counting, counts from 37426 to 37429 were combined and halved, recognising this may modestly underestimate malleable prosthesis rates.

3. Results

3.1. Overall Temporal Trends

Between 1996 and 2024, 251 815 second‐ and third‐line ED treatment initiations were recorded nationally, comprising 242 874 in‐office ICI and 8941 PPI as shown in Figure 1. ICI utilisation declined sharply from a peak of 591.4 per 100 000 men in 1997 to 10.8 per 100 000 men in 2024, representing an absolute reduction of ~580 cases per 100 000 men and a greater than 55‐fold relative decline. Decade‐specific reduction CAGR presented in Table 1 demonstrated a rapid collapse in the late 90s (−22.3%/year, 1996–1999) and the early 2000s (−21.8%/year 2000–2009), with a relative stabilisation in the 2010s (−4.7%/ year) and steeper decline in the 2020s (−10.3%/year).

FIGURE 1.

Overall utilisation of second‐ and third‐line erectile dysfunction therapies. (A) Overall utilisation of intracavernosal injection therapy 1996–2024 standardised per 100 000 Australian men. (B) Overall utilisation of penile prosthesis insertion 1996–2024 standardised per 100 000 Australian men. (C) Unadjusted overall utilisation of intracavernosal injection therapy 1996–2024. (D) Unadjusted overall utilisation of penile prosthesis insertion 1996–2024.

TABLE 1.

Compound annual growth rate second‐ and third‐line ED treatments per decade.

Period	ICI start	ICI end	ICI CAGR (%/year)	Prosthesis start	Prosthesis end	Prosthesis CAGR (%/year)
1996–1999	323.0	152.0	−22.3	2.60	1.07	−25.7%
2000–2009	225.0	24.5	−21.8	1.13	2.09	+7.1
2010–2019	25.0	16.1	−4.7	2.45	3.72	+4.7
2020–2024	16.6	10.8	−10.3	3.32	3.59	+1.9
Overall	323.0	10.8	−11.4	2.6	3.59	+1.1

In contrast, PPI utilisation remained low but demonstrated progressive growth with an overall increase of 2.6–3.59 procedures per 100 000 men between 1996 and 2024 (CAGR of 1.11%/ year). An initial contraction in the late 90s (CAGR −25.7%) was followed by a sustained rise in the following decades (+7.1% CAGR, 2000–2009 and +4.7% CAGR, 2010–2020), with a plateau thereafter (+1.0% CAGR, 2020–2024) as displayed in Table 1.

3.2. Age‐Specific Utilisation Patterns

The use of ICI therapy was highest in men aged 55–74 during the late 1990s, peaking at 1700–1750 procedures per 100 000 men. Following this peak, there was a decline across all age groups. By 2024, ICI rates had fallen to less than 5 per 100 000 men in the 25–34, 35–44, and > 85 age brackets and to ~30–39 per 100 000 in the previous highest‐utilising 55–74‐year age groups.

Age stratification showed prosthesis use was more common in older men (Figure 2). From 1996 to 2024, the highest rates of PPI utilisation were most consistently observed in the 65–74‐year age bracket, showing growth from ~9.79 to 16.60 per 100 000 men. The 75–84 age bracket showed the largest relative increase in utilisation over the study period, from 2.24 per 100 000 men in 1996 to a peak of 10.73 per 100 000 men in 2023.

FIGURE 2.

Age‐stratified utilisation of second‐ and third‐line erectile dysfunction therapies. (A) Age‐stratified utilisation of intracavernosal injection therapy from 1996 to 2024 per 100 000. (B) Contemporary age‐stratified utilisation of intracavernosal injection therapy from 2010 to 2024 per 100 000. (C) Age‐stratified utilisation of penile prosthesis insertion from 1996 to 2024 per 100 000.

3.3. Geographic Variation in Access

Population‐adjusted ICI utilisation demonstrated a consistent decline across all Australian states, mirroring nationwide trends. Table 2 shows all states demonstrated a peak in 1997, with New South Wales and Queensland demonstrating the highest peak utilisation with 657 and 634 men per 100 000, respectively in 1997. Utilisation then collapsed rapidly, family 60%–75% by 1999 across all states, with continued further decline over the following decades. Queensland (~15/100 000) and Western Australia (~21/100 000) retained slightly higher relative contemporary utilisation, but rates remained very low nationally, representing a > 95% reduction from peak activity.

TABLE 2.

State‐stratified prosthetic utilisation over time.

State	1996 rate	2024 rate	Absolute change	Relative change
NSW	2.30	3.24	+0.94	+41%
VIC	1.91	3.21	+1.30	+68%
QLD	2.76	5.37	+2.61	+95%
SA	2.68	2.41	−0.27	−10%
WA	4.30	3.96	−0.33	−8%
TAS	6.39	1.23	−5.16	−81%
ACT	1.95	1.69	−0.26	13%
NT	1.01	0.00	−1.01	—

Penile prosthesis utilisation has demonstrated gradual and sustained growth across most Australian states from 1996 to 2024 as shown in Table 2. All states demonstrated a reduction in utilisation in the late 90s, with recovery by the early 2000s (Figure 3). Queensland and Victoria have seen the largest relative increase in utilisation, rising from ~2.8 and ~1.9 per 100 000 men in 1996 to ~5.4 and ~3.2 per 100 000, respectively by 2024. South Australia and Western Australia show variable trajectories, with early rates comparable to other states but failed to demonstrate a net increase by 2024. Despite inter‐state variation, there was no evidence of long‐term decline, with all states showing relative stability or modest growth over the study period.

FIGURE 3.

Geographic variation in second‐ and third‐line ED therapies. (A) Intracavernosal injection utilisation stratified by state 1996–2024. (B) Penile prosthesis utilisation stratified by major states 1996–2024. (C) Heatmap of penile prosthesis utilisation of all Australian states and territories 1996–2024.

3.4. Economic Impact and Funding Patterns

Aggregate government rebates for invasive ED treatments peaked at ~AUD $1.7 million in 1997. Expenditure dropped sixfold by 2004 to a combined expenditure of AUD $248 710 followed by a slow growth, stabilising in 2014 at ~AUD $550 000 annually, highlighted in Figure 4. A temporary reduction in expenditure was seen during the COVID pandemic (2019–2022), followed by a recovery in 2023–2024. Relative contribution has shifted from ICI (~90% of rebates in the late 1990s) to PPI, which has comprised most of the annual rebate outlay since 2005. ICI rebates fell to ~AUD $100 000 annually by the 2010s, whereas PPI rebates increased modestly with increased utilisation in the 2000s and have largely remained stable since 2015 (~AUD $400 000–450 000). These figures represent Medicare rebates only and therefore underestimate true health‐system and patient costs.

FIGURE 4.

Medicare expenditure of second‐ and third‐line ED therapy 1996–2024 in AUD.

3.5. Pharmacotherapy Subsidy Trends

From 1999 to 2024, RPBS prescriptions for PDE5‐Is rose from 440 in 1999 to ~25 500 in 2024. Sildenafil, being the first PDE5‐I approved in Australia, dominated early use to a peak of 25 476 in 2002. Tadalafil entered the market in 2004 (5078) and demonstrated a steady increase in utilisation patterns to 14 638 in 2024. This rise coincided with a steady reduction in sildenafil use to 10 277 in 2024. As of 2024, Tadalafil accounts for 58% of PDE5‐I utilisation, with Sildenafil contributing 40%. Avanafil was introduced in 2019 and remains a small contributor to overall utilisation. Total RPBS benefit over the study period was $57 557 535. Benefits rose sharply from 1999 to 2009, from $26 769 to $275 473, after which yearly benefits stabilised (Figure 5).

FIGURE 5.

(A) RPBS utilisation of eligible PDE5‐I 1999–2024 (total prescriptions/year). (B) RPBS cost of PDE5‐I 1994–2024 (in AUD). (C) RPBS utilisation of alprostadil 1999–2024 (total prescriptions/year).

National utilisation of alprostadil demonstrated an initial rise following RPBS approval from 506 in 2003 to a peak of 2856 in 2004. This was followed by a gradual decline over the next decade, with annual prescriptions falling steadily from 2481 in 2005 to 813 in 2014. A marked and isolated trough was observed in 2015 with only five recorded prescriptions, followed by a rapid rebound in 2016. Alprostadil trends mirror those of overall ICI utilisation patterns, with a sustained decline over time.

4. Discussion

ED management has seen profound change over the past 30 years in Australia. This national, population‐adjusted analysis has demonstrated changing trends in intracavernosal therapy, with ICI use falling by more than 55‐fold and stabilising at very low levels. In contrast, PPI demonstrated stable growth, particularly in men over the age of 65, with the most marked rise seen in those aged 75–84 years, consistent with an expanding ageing population with complex and refractory ED. Government expenditure has shifted accordingly, with PPI comprising most of yearly ED expenditure. These findings illustrate a sustained shift in practice patterns and provide a benchmark for health‐service planning and international cohort comparison.

The decline seen in ICI utilisation in the post‐PDE5‐I era is well documented internationally. Similar sharp declines have been seen in the United States, with Wysowski demonstrating a ~33% reduction in national ICI utilisation from 1998 to 2001 [20], with similar trends demonstrated in Asia [17]. International literature also mirrors the observed trends in PPI utilisation in Australia, with some notable regional differences. Population‐level studies in the United States showed a decline in prosthesis use in the 1990s and early 2000s [21, 22]. More recently, a systematic review and data from device manufacturers indicate global growth in prosthesis utilisation [19, 23].

The disproportionate rise among older men is particularly notable. While increasing age increased ED prevalence, age‐standardised growth suggests a shift in clinical practice and patient expectations that goes beyond an ageing population. This shift is likely multifactorial, reflecting an interest in population ageing, improved prostate cancer survivorship, and an evolving view on sexual function later in life. In Australia, where 5‐year prostate cancer survival now exceeds 95% [24] with many men living with persistent treatment‐related ED may be increasingly seeking durable improvement in sexual function as part of survivorship care.

Despite an expanding population of men with medically refractory ED, overall uptake of second‐ and third‐line therapies remains low. Despite many men reporting poor erections with PDE5‐I [13], conversion to ICI therapy is not common, and similarly, the uptake of penile prosthesis implantation remains low. The discordance between the expected pool of men with medically refractory ED and those progressing to further treatment may suggest a gap between guideline recommendations and real‐world practice. Potential contributors include financial and location barriers, limited patient awareness, variability in clinician expertise, limited access to specialist care and fragmented referral pathways between primary care, oncology services and sexual medicine specialists. This raises the possibility of a significant number of Australian men with refractory ED who are not receiving effective therapy [25], missing an opportunity for quality‐of‐life improvement.

The decline of ICI utilisation has several clinical implications. Reduced clinical exposure may limit confidence and training in injection therapy prescribing [26] despite its recognised role as second‐line therapy for drug‐refractory ED and in post‐prostatectomy rehabilitation. Meanwhile, growth in prosthesis utilisation must be supported by adequate workforce training and improved access to high‐volume prosthetic centres. The recent plateau may reflect saturation among men most likely to seek and access prosthetic surgery as opposed to saturation in underlying need. Alternatively, surgical capacity may be a limiting factor. Prosthesis surgery remains a niche within Australian urology, predominantly performed in high‐volume private centres by a limited number of urologists with specialised training. As the population of men living with complex and refractory ED continues to expand, future service provision, especially to patients in regional and public settings, may be required to prevent restricted access.

This study highlights health‐system factors unique to Australia. The MBS influences utilisation patterns, including the lack of widespread subsidy of PDE5‐Is and alprostadil and the partial subsidy of prosthesis surgery. As a result, socioeconomic and geographic disparities likely influence access to second‐ and third‐line treatment options. Further investigation is needed to understand and quantify these disparities for improved workforce planning. Establishing streamlined referral pathways, developing multidisciplinary sexual rehabilitation programmes, and improving awareness in primary and tertiary care may help mitigate structural barriers to care.

This study has notable strengths, including a long‐term longitudinal epidemiology, age and state‐specific stratified analysis, as well as national coverage of subsidised medications and procedures. However, we acknowledge some of the limitations in our study. Primarily, the use of administrative claims data lacks patient‐level clinical detail including indication, disease severity, treatment outcomes and patient preferences. Furthermore, the dataset does not permit adjustment for important confounders such as comorbidities, ethnicity, socioeconomic status, or regional practice variation. Moreover, reliance on MBS data underestimates total national utilisation, as procedures performed in public hospitals are not captured. Complexity in coding for prosthesis reimbursement means that the study underestimates malleable prosthesis utilisation, and may inadvertently capture some revision cases, as some surgeons may use both item numbers instead of a single number 937432 in revision cases. The item number for ICI (37415) does not distinguish ICI used for diagnostic purposes (e.g., penile duplex ultrasonography) from therapeutic use, nor does it capture ongoing home utilisation. Additionally, coding practices and reimbursement structures may have changed over time, potentially influencing utilisation estimates. While the item number likely captures men being initiated on ICI therapy, as guidelines recommend the first injection to occur in the office, it underestimates total treatment exposure. Cost analysis performed only reflects Medicare rebates, and excludes device and medication costs, private health charges, surgeon fees and hospital costs, significantly underestimating total expenditure. Lack of clinical detail regarding indication, comorbidity burden, prior treatment and treatment pathways restricts inference; however, the large national dataset provides compelling evidence of real‐world changes in practice.

5. Conclusions

This study provides the first national‐level, population‐adjusted analysis of invasive ED treatments in Australia using 30‐year MBS trends. Rates of ICI have declined precipitously over time, with a marked change in utilisation observed following the introduction of PDE5‐Is. PPI similarly decreased during the early PDE5‐Is era; however, utilisation has increased since the 2000s, particularly among men aged over 65 years. These findings describe evolving patterns in second‐ and third‐line ED management in the context of broader therapeutic developments. Incorporating national Medicare rebate data provides insight into procedure trends beyond oral therapy. Further research incorporating patient‐level data is needed to better understand determinants of treatment selection and contemporary practice patterns.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.