Global and regional quality of care index for prostate cancer: an analysis from the Global Burden of Disease study 1990–2019

Prostate cancer (PCa) is the second most incident cancer among men worldwide, affecting more than 1.4 million cases annually [1]. From 1990 to 2017, the age-standardized incidence rate (ASIR) of PCa had increased from 30.5 to 37.9 per 100,000, globally [2]. In the same period, although the total number of PCa related deaths had nearly doubled, the age-standardized death rate (ASDR) had dropped by 2.1 percent [2]. High socio-demographic index (SDI) regions experienced sharp declines in PCa ASDR from 1990 to 2017, while regions with lower SDIs showed slighter decreases or even increases of ASDR in the same period [2].

The World Health Organization defines quality of care (QoC) as the degree to which health services increase the chance of desired health outcomes [3]. The American Society of Clinical Oncology has, in a statement, highlighted some of the disparities present in cancer care in the United States [4] and has since provided guidance on how to reduce these discrepancies and overcome the challenges [5, 6]. Despite all efforts, healthcare inequalities exist even in high-income countries, let alone countries with lower incomes. Countries with better QoC, if identified, could serve as role models for other nations.

Several studies have developed indices to measure the quality of patient care [7, 8]. However, a reliable numerical QoC indicator that could be used for all diseases is yet to be defined. In this study, we present the newly introduced “quality of care index” (QCI) [9] and implement it on PCa data obtained from the Global Burden of Disease (GBD) study 1990–2019 [10] in order to achieve a global overview on PCa QoC and potentially assist healthcare experts and policy-makers in improving it.

Globally, ASIR and ASR of YLDs of PCa have increased from 1990 to 2019, while ASDR and ASR of DALYs and YLLs have decreased. Furthermore, the rate of DALYs has decreased in high and high-middle SDI regions and increased in regions with middle, low-middle, and low SDIs. Prostate cancer QoC has increased globally and in every SDI region over the 30-year period.

The increase in PCa incidence in the early 90 s could largely be attributed to the introduction of PSA as a screening method [28]. The trend later leveled off, most likely due to overall healthcare improvements around the globe and the success of preventive measures including early detection. Difference in PCa screening, diagnosis, and management is a logical explanation for the QCI gap between high and low SDI regions [29]. Furthermore, low-middle and middle SDIs were the only quintiles with significant ASIR increases from 1990 to 2019. This might be due to the persistence of ineffective screening in low SDI countries and successful control and prevention of the disease in high-middle and high SDI regions. Reduced PSA testing as recommended by the newest guidelines could have also contributed to reduced PCa incdince in high income countries [2, 30].

QoC indicators enables regulatory organizations to develop new policies and evaluate the existing ones more accurately. The QCI has unique qualities compared with other QoC indicators [26, 27, 31]: it is easily calculated from basic epidemiological indices, could be applied to all diseases [13-15] and demographic classifications, and most importantly, produces a single numerical index that is objectively interpreted and is capable of being compared between groups.

Global PCa QCI has increased by nearly 14% since 1990. Regions with higher SDIs and high-income regions have had higher QCIs throughout the years, and all of the countries on top of the QCI ranking are highly developed nations. On the other hand, the bottom of the list mainly comprises African countries with low SDIs. This is unsurprising, given the heavy costs of PCa on economies and individuals [32-35].

Nevertheless, our findings indicate that sub-Saharan countries with relatively high SDIs (such as South Africa with SDI = 0.68) have QCIs well below the global average (South Africa 2019 QCI = 47.1), similar to other nations of the sub-Saharan Africa. This highlights the role of contributing factors other than income and socio-demographic development. These include lack of information about the disease [36], screening policies [36], and local guidelines optimized for the region [35]. Ethnicity also plays a role; for instance, African-American ethnicity is a known risk factor of PCa and the disease’s burden is heavy in countries where many people are from African origins [2, 37].

The effect of prostate-specific antigen (PSA)-based screening on QCI is evident in many of our findings. QCI surged in many countries in the mid 1990s, which is most likely due to introduction of PSA and its subsequent approval by the US Food and Drug Administration as a screening tool for prostate cancer [38]. However, in 2009, the results of two large clinical trials [39, 40] questioned the benefits of PSA screening, and consequently, policymakers revisited their stance on PCa screening. The updated American Cancer Society guidelines for PCa screening in 2010 [41] emphasized on a more patient-oriented approach rather than the strong recommendations in favor of PSA-based screening presented in the previous 2001 guidelines [42]. Later in 2012, the United States Preventive Services Task Force (USPSTF) released a statement recommending against PSA screening (grade D), for all age groups [43]. These alterations led to many unfavorable outcomes. According to two studies in the US [44] and Australia [45], the 2012 statement resulted in a higher risk of harboring a more aggressive disease upon diagnosis. In countries with high PCa QCIs (e.g., the USA, New Zealand, and Australia) and high SDI regions, ASRs of mortality, DALYs, YLDs, and YLLs, which had constantly been decreasing, have started to rise in the past few years, resulting in the cessation of the upward trend of QCI in these regions. Finally, in 2018, USPSTF changed its stance on PSA-based screening from “discouraged in all age groups” (grade D) to “individualized recommendation in ages 55 to 69” (grade C) [46], which is similar to American Urological Association’s guidelines [47]. It is a matter of time to see whether this change affects PCa burden and quality of care or not. Our results are in favor of PSA screening as QCI had increased whenever policies were in favor of screening and decreased when screenings were limited, although PSA testing could lead to overdiagnosis and overtreatment, and consequently, therapy complications such as incontinence and erectile dysfunction. Further studies and trials are required to clarify the benefits or disadvantages of PSA-based PCa screening. In addition, novel biomarkers are constantly being developed, which might have better diagnostic accuracy than PSA and reduce the adverse effects of overtreatment [48, 49].

Age disparity analyses revealed that QCI was lowest in both age extremities and peaked in middle-aged patients (ages 50 to 69 years) in 2019. Older PCa patients are more likely to have a more aggressive disease [50, 51] and are at higher chance of biochemical recurrence after treatment [51]. Also, younger PCa patients with advanced disease are at higher risk of poor outcomes [52, 53], although disease mortality in young patients regardless of their disease stage is of controversy [52-55] and unlike the elderly [50], no definite marker or genetic component for severe disease has been identified in these patients [54, 56]. One explanation for these findings could be the fact that guidelines do not recommend offering PCa testing to men > 70 years old and/or those with life expectancies < 10 years, and therefore, these patients are missed in the preliminary asymptomatic stages. The same is true for younger patients as PSA testing is only recommended to be discussed with patients above 40, 45, 50 or 55 years of age (depending on risk factors and the guideline) [41, 46, 47, 57].

Analyzing healthcare systems and practice guidelines of regions with continuously rising QCIs could guide experts in improving current protocols and guidelines. One outlier is Turkey, in which an abrupt increase of QCI is seen in 2003 and has persisted through 2019. The healthcare reform of Turkey (2003–2010) [58] is undoubtedly one of the main factors behind this improvement and could act as a role model for policymakers in other nations.

Our study is the first to evaluate quality of care of prostate cancer in a quantifiable method and developed the QCI at global and regional levels. The newly introduced QCI has valubale implications in public health, such as helping experts identify and understand disparities of quality of care between different groups and regions, and guiding organizations and societies through establishing healthcare policies to overcome PCa care challenges. Nonetheless, our study bears several limitations. Our data are acquired from the GBD database, and therefore, any limitation applying to it also applies to our study. Since GBD estimates its measures from various sources and using complex statistical methods, the results are subject to uncertainties. In addition, there are no classifications based on demographic characteristics such as race and risk factors. Furthermore, utility of a calculated QCI is limited to that disease and QCIs of different diseases could not be compared to each other. Moreover, we were unable to calculate uncertainty intervals for all calculated indices due to limited computational resources. Currently available literature implementing the QCI, to the best of our knowledge, are limited to our institution and additional studies by other research groups are required to further evaluate the QCI.

Prostate cancer QoC has improved in the 1990–2019 period, as measured by the QCI. Regions with higher SDIs have better QoC, as demonstrated by QCI, which is mainly due to more effective healthcare systems and early initiation of screening. Factors other than socio-demographic development also contribute to PCa QoC, such as patient education, the healthcare system, and the presence of practical guidelines. Although PSA screening is a matter of debate and is nowadays not as strongly recommended as before, our study shows that QCI has decreased since the introduction of updated guidelines, including statements against routine PSA screening. We also compared QCI in different age groups and found that patients with either very low or very high age experience lower quality of care, which could be attributed to factors such as the more aggressive nature of the disease, undertreatment, and lack of PSA screening in these age groups. The results of our study could be used to identify disparities in healthcare and assist public health experts in taking appropriate actions in improving PCa QoC, such as modifying screening guidelines and resource allocation.