Impact of Prostate Cancer Diagnosis on Non-Cancer Hospitalizations among Elderly Medicare Beneficiaries with Incident Prostate Cancer

Abstract

OBJECTIVES

To analyze the impact of cancer diagnosis on non-cancer hospitalizations (NCHs) by comparing these hospitalizations between the pre- and post-cancer period in a cohort of fee-for-service Medicare beneficiaries with incident prostate cancer.

METHODS

A population-based retrospective cohort study was conducted using the Surveillance, Epidemiology and End-Results (SEER) -Medicare linked database for the years 2000 to 2010. The study cohort consisted of 57,489 elderly men (≥ 67 years) with incident prostate cancer. NCHs were identified in six time periods (t₁–t₆) before and after the incidence of prostate cancer. Each time period consisted of 120 days. For each time period, NCHs were defined as inpatient admissions with primary diagnosis codes not related to prostate cancer, prostate cancer-related procedures or bowel, sexual and urinary dysfunction. Bivariate and multivariate comparisons on rates of NCHs between the pre- and post-cancer period accounted for the repeated measures design.

RESULTS

The rate of NCHs during the post-cancer period (5.1%) was higher as compared to the pre-cancer period (3.2%). In both unadjusted and adjusted models, elderly men were 37% (Odds Ratio, OR: 1.37, 95% Confidence Interval, CI: 1.32, 1.41) and 38% (Adjusted OR: 1.38, 95% CI: 1.33, 1.46) more likely to have any NCH during the post-cancer period as compared to the pre-cancer period.

CONCLUSIONS

Elderly men with prostate cancer had a significant increase in the risk of NCHs after the diagnosis of prostate cancer. The study highlights the need to design interventions for reducing the excess NCHs after diagnosis of prostate cancer among elderly men.

INTRODUCTION

The period immediately following the cancer diagnosis can be considered as a point of turbulence for the management of pre-existing chronic conditions. Cancer is often considered as a dominant condition that eclipses the management of all other chronic conditions (1). Among individuals with cancer, the management of chronic conditions that are not related to cancer may be neglected (2). Undermining the management of chronic conditions in cancer may result in adverse outcomes and poor quality of care for non-cancer related conditions in cancer. For example, among elderly men with localized prostate cancer survivors the quality of care for acute chronic conditions are neglected (3). Further, among men of all ages with prostate cancer, many hospitalizations are attributable to chronic conditions other than prostate cancer. For example, using the encounter-level data for the years 1997 through 2004, Milenkovic et al. found that among adults with prostate cancer, 84% of the inpatient encounters were for chronic conditions other than prostate cancer (4). While these studies confirm the burden of non-cancer hospitalizations among men with prostate cancer, the changes in hospitalizations due to non-cancer conditions over a period of prostate cancer diagnosis remain unknown due to the use of encounter level.

An understanding of the risk of NCH risk after the diagnosis of cancer for those with incident prostate cancer is critical to better manage care at the time of incident prostate cancer. Therefore, the primary objective of the current study is to analyze the impact of cancer diagnosis on NCHs among elderly men with incident prostate cancer by comparing the rates of NCHs in six periods during pre-and post-cancer diagnosis period.

Furthermore, elderly men with prostate cancer have differential rates of chronic conditions. For example, cardio-metabolic conditions (example: heart disease and diabetes) are observed in 18.1% of men with prostate cancer, followed by respiratory conditions (example: chronic obstructive pulmonary disease-9.8%) (5) and mental health conditions (example: depression-8%) (6). Thus, the risk for hospitalizations may differ by the types of chronic conditions. One study, not specific to prostate cancer, reported that individuals with cardio-metabolic conditions had higher rates of annual hospitalizations (40%) as compared to those with respiratory conditions (20%) among adults aged 50 years and older in the US (7). The incidence of prostate cancer can have varying impact on the risk for NCHs among individuals with different types of chronic conditions. Therefore, the secondary objective of our study is to examine whether the impact of cancer diagnosis on NCHs differs by the types of chronic conditions.

METHODS

Study Design

Post-diagnosis

A retrospective longitudinal cohort design with baseline, pre and post-cancer periods were used. Using the date of cancer diagnosis as the index date, a 24-month window before the index date was constructed. This 24-month period was split into two 12-month periods (i.e. baseline and pre-cancer period). This was necessary because identification of pre-existing chronic conditions and NCHs during the pre-cancer period involved the use of inpatient claims. To avoid circular reasoning, the first 12-month period was used as the baseline period, during which the types of chronic conditions and other independent variables were measured. The 12-month period before the diagnosis of cancer was considered as the pre-cancer period and this period was used to derive NCHs. The post-cancer period also consisted of 12 months after the diagnosis of cancer. To ensure a robust study design, the NCHs were measured repeatedly every 120 days during the pre- and post-cancer period, yielding a total 6 repeated measures per individual. Thus, t₁, t₂, t₃ represented the pre-cancer period and t₄, t₅, and t₆ represented the post-cancer period. (See Figure 1 for details).

Figure 1.

Study design

Data Sources

SEER-Medicare Linked data

We utilized the National Cancer Institute’s (NCI) SEER cancer registries data linked with Medicare administrative claims data. As of now, the SEER data represents 28% of US population from 18 registries and consists of a total of 7,397,159 malignant cancers cases and majorities of these cancer cases are diagnosed among the elderly population aged 65 years and over (8). The Medicare is the US Government mandated insurance program covering 97% of the US population aged 65 years and older (9). A total of 93% percent of men aged 65 years and older in SEER has been linked to Medicare enrollment records (10) (9). In the current study, we utilized data from the SEER-Medicare linked database of prostate cancer cases diagnosed between 2002 and 2009 and their linked claims between 2000 and 2010. Furthermore, we included elderly men 67 years and older as we required at least two years of healthcare utilization data before diagnosis of prostate cancer.

Study Cohort

The study population was based on 289,701 men diagnosed with incident prostate cancer between January 1^st 2002 and December 31^st 2009. Men with multiple cancers (N =25, 785); diagnosed with prostate cancer during the autopsy (N = 2,944); men younger than 67 years of age and died during the study period (N = 111,643) were excluded. Further, the cohort was further restricted to those with continuous fee-for-service Medicare Part A and Part B enrollment during the entire study period (N = 101,302). To reduce the misclassification bias, individuals with newly diagnosed conditions during the pre-cancer and post-cancer periods (N = 40,544) were excluded. After excluding individuals with missing information on race/ethnicity, county, and in-situ, unknown, and advanced cancer stage, the final study cohort comprised of 57,589 elderly men with incident prostate cancer (see. Figure 2 for details).

Figure 2.

Study Cohort Development Chart for Study Population of Elderly Medicare Beneficiaries diagnosed with Prostate Cancer

Key Dependent Variable

NCHs

Inpatient admissions during the pre- and post-cancer periods were derived from the MEDPAR file. Hospitalizations with the primary diagnosis of prostate cancer were considered as prostate-cancer-related hospitalizations and were excluded from the analysis (4). Although such approach is commonly used in published studies to identify disease-specific hospitalizations (11, 12), the challenges in measuring the NCH should also be noted. Elderly men with prostate cancer may have hospitalizations due to cancer-related complications such as bowel, sexual or urinary dysfunction or cancer-related procedures such as surgery. Therefore, the NCHs were considered as the any admission to an inpatient facility with a principal diagnosis for conditions other than prostate cancer or hospitalizations for cancer-related complications-bowel, sexual and urinary dysfunctions or primary or treatment related-procedure codes for cancer-related procedures. The details of the codes used to identify the cancer related-complications and procedures are listed in the Appendix 1&2.

Independent Variables

Our study utilized a widely known the Andersen Healthcare Utilization and Behavioral Model (ABM) to identify the potential independent factors associated with non-cancer-related hospitalizations in our study population (13). The ABM model and adapted versions of this model have been extensively used in the health services research to study the factors associated with the healthcare service use and healthcare outcomes. The ABM model states that the use of healthcare services is determined by individual and contextual determinants. These determinants can be categorized into four groups: 1) Predisposing factors, 2) Enabling factors, 3) External environment and 4) Need factors (Please see Figure 3 for details).

Figure 3.

Study Theoretical Framework: Adaptation of Andersen Behavioral Model

Predisposing Characteristics

These factors represent the unique feature of individuals that tend to represent more or less use the healthcare services. Age, race/ethnicity, and marital status were the predisposing characteristics. Age at the time of diagnosis (67 to 74 years, 75 and above years), race/ethnicity (White, African American, Hispanic, and other), and marital status (married, divorced/separated, unmarried, and others) were identified from the PEDSF file.

Enabling Characteristics

These factors serve as conditions that enable individuals to use healthcare services. Income, education, access to care and the initial cancer treatment were the enabling factors. The PEDSF file provides 2000 census-level information as education level and median income. Access to care was measured with at least one visit to a primary care provider during the baseline period (14). Receipt of active treatment was identified using inpatient, outpatient and carrier files with appropriate ICD-9 CM diagnostic and procedure codes, CPT or HCPCS codes or Revenue Center code during the six months after the index date (Appendix 1)(15, 16), (17). We classified the cancer treatment into four groups based on a hierarchy: 1) Radical Prostatectomy (RP); 2) Radiation Therapy (RT); 3) Hormone Therapy; and 4) None of the RP, RT or hormone therapy.

External environment characteristics

These are the set of factors facilitating the use of healthcare services related to the structure of services in the geographical areas near to the individuals. External environment characteristics comprised of the individual’s region (Northeast, South, North-Central, and West) and county-level healthcare resources such, radiation-oncology units and urology units. (18). County-level healthcare resources were measured by the number of radiation oncology units and urology units, which were derived from the Area Healthcare Resource files (AHRF). For the purposes of our analyses, we categorized the number of radiation oncology units and urology units into four groups using quartiles.

Need Characteristics

These are the factors requiring the need to use healthcare services at the individual level. We classified the common types of chronic conditions using the organ domains (19). We selected this approach because of the synergism in treatment and self-management approaches. For example, the management of cardio-metabolic conditions such as diabetes and heart disease have similar treatment and self-management strategies. Among men with prostate cancer, cardio-metabolic diseases (diabetes, and heart disease), respiratory diseases (COPD and asthma), and mental health conditions (depression, and other mental conditions) are commonly reported. These common chronic conditions were classified into seven mutually exclusive categories: (1) cardio-metabolic conditions only; (2) mental health conditions only; (3) respiratory conditions only; (4) cardio-metabolic and mental health conditions, (5) cardio-metabolic and respiratory conditions, (6) having all the three types of chronic conditions, and 7) having none of the three types of chronic conditions. Due to insufficient numbers for the category “respiratory and mental health conditions”, this category was excluded from analysis. All the chronic conditions were identified during the baseline period using one inpatient claim or two outpatient claims for each of the chronic conditions listed in Appendix 3. A very small percentage of men (<5%) had chronic conditions other than the cardio-metabolic, mental-health, and respiratory conditions. Forty-two other conditions were derived using the list of chronic conditions from published literature (1). We calculated the total number of other chronic conditions during the baseline period and categorized as “zero or one condition” and “two or more conditions”. The American Joint Committee on Cancer (AJCC) Tumor-Node-Metastases (TNM) stage classifications was utilized for staging of prostate cancer. The cohort was restricted to elderly men with no-node positive or non-metastatic prostate cancer. Three groups of cancer stage at diagnosis were created as: 1) T1 or less; 2) T2 and 3) T3 or T4.

Statistical Analyses

As the NCHs were measured repeated during each of the six-time periods, the observations are no longer independent and are correlated. To account for correlated data, we utilized a statistical approach suggested by Liang et al (20). This method involves the use of the generalized estimating equations (GEE) with specific the correlation-matrix. The general form of the model is given in the equation below.

$$\mathit{ln}(\frac{p_{\mathit{ij}}}{1-p_{\mathit{ij}}})={\beta }_0+{\beta }_1({\mathit{\text{time}}}_{\mathit{ij}})+{\beta }_2{(CC)}_i+\cdots +{\beta }_n{(N_{\mathit{th}}\mathit{\text{Variable}})}_i$$

where p_ij denotes the probability of NCHs for individual i, in time period j. Time_ij denotes a specific time period j for an individual, i. CC_i denotes presence of particular types of chronic conditions at baseline period for an individual, i. The model also included other independent variables such as predisposing, enabling, need and external-environment characteristics measured for an individual, i. βs are the regression coefficients to be estimated. We specified three types of correlation structures – exchangeable, autoregressive, and unstructured –to control for correlations between repeated observations (21). As the parameter estimates of the association between NCH and types of chronic conditions remained the same under different correlation structures, only the results from GEE models with exchangeable correlation structure are reported. For ease of interpretation, the predicted probabilities of NCHs between the pre-and post-cancer period were compared. These probabilities were calculated using the parameter estimates from the GEE models, assuming an additive effect (22). Statistical analyses using GEE models were carried out in Stata Statistical Software: Release 13 (STATA-13). The predicted probabilities were derived using the “margins” command in STATA-13. The term “risk” is used to describe the results associated with odds ratios (OR). Although the risk ratio and OR will yield different estimates, for events with low prevalence (≤ 10%) (23) such as NCHs, these two measures will produce similar results.

RESULTS

Study Population

The study cohort (N = 57,489) was primarily whites (82.4%), in the age group 67–74 years (58.3%, mean age = 74.6 years, standard deviation = 5.1), married (68.5%). Most men in the study cohort received treatment for cancer (80.5%) see Table 1 for details.

Table 1.

Characteristics of Elderly Medicare Beneficiaries with Incident Prostate Cancer Surveillance, Epidemiology and End Results (SEER)-Medicare Linked Database 2000 – 2010

	N	%
All	57,489	100
Types of Chronic Conditions
CM only	21,712	37.8
MH Only	813	1.4
RSP only	2,277	4.0
CM + MH	1,148	2.0
CM + RSP	5,114	8.9
None	25,811	44.9
All Three	614	1.1
Predisposing Characteristics
Age at diagnosis, in years
66–74	33,495	58.3
75+	23,994	41.7
Race/ethnicity
Whites	47,384	82.4
African-American	6,272	10.9
Hispanic/Latino	1,011	1.8
Others	2,822	4.9
Marital status
Unmarried	3,654	6.4
Married	39,386	68.5
Divorced/Separated	6,993	12.2
Others	7,456	13.0
Enabling Characteristics
Quartile of median census 2000 income
$ 7–$ 34,522	14,362	25.0
$ 34,523–46,224	14,368	25.0
$ 46,229–62,764	14,369	25.0
$ 62,767–200,008	14,390	25.0
Quartile of median census 2000 education
0–8.52	14,371	25.0
8.53–15.16	14,376	25.0
15.17–26.09	14,373	25.0
26.1–100	14,369	25.0
Visit to a PCP
Yes	37,405	65.1
No	20,084	34.9
Active Treatment
RP	11,520	20.0
RT	29,234	50.9
Hormone Therapy	5,510	9.6
No Treatment	11,225	19.5
External-Environment Characteristics
SEER-Regions
Northeast	11,360	19.8
South	14,095	24.5
North-Central	7,288	12.7
West	24,746	43.0
Quartile of Radiation Oncology
0 to 1	15,127	26.3
2 to 6	13,203	23.0
7 to 22	14,739	25.6
23 to 147	14,420	25.1
Quartile of Urology Centers
0 to 3	14,107	24.5
4 to 16	14,390	25.0
17 to 44	14,130	24.6
45 to 343	14,862	25.9
Year of Diagnosis
2002–2005	28,275	49.2
2006–2009	29,214	50.8
Need Characteristics
Number of Other Chronic Conditions
≤ One	38,435	66.9
> One	19,054	33.1
T-Stage
≤T1	32,063	55.8
T2	23,905	41.6
≥ T3	1,521	2.6

Notes: Notes: Based on 57,489 elderly men, aged 67 years and older, diagnosed with incident prostate cancer between 2002 and 2009 and alive throughout the observation period.

Abbreviations: CM: Cardio-metabolic conditions; MH: Mental health conditions; PCP: Primary Care Physician; RESP: Respiratory conditions; RP: Radical Prostatectomy; RT: Radiation Therapy

Non-cancer-Hospitalizations during the pre- and post-cancer period

Table 2 reports the rates of non-cancer-hospitalizations during each of the time periods. The rates of non-cancer-hospitalizations were the highest during the post-cancer period (t_4, i.e., 120 days immediately after the cancer diagnosis) and lowest during the pre-cancer period (t₂) (5.1% vs 3.2%), an increase of 1.9 percentage points. Of all the categories of chronic conditions, the rates of NCHs during the post-cancer were significantly higher compared to the pre-cancer period. Among elderly men with all the three types of types of chronic conditions, the rates were 20.8% during the post-cancer period (t₅) and 14.3% during the pre-cancer period (t₃), an increase of 6.5 percentage points. Among elderly men with none of the chronic conditions, the rates were 2.6% during the post-cancer period (t₄) and 1.3% during the pre-cancer period (t₁), an increase of 1.3 percentage points. Similar increases were seen for other chronic condition categories.

Table 2.

Number and Percentage with Non-Cancer Related Hospitalizations during the Pre- and Post-Cancer Period Elderly Medicare beneficiaries with Incident Prostate CancerSurveillance, Epidemiology and End Results (SEER)-Medicare Linked Database-2002–2010

	Pre-Cancer Period						Post-Cancer Period
	t1		t2		t3		t4		t5		t6
	N	%	N	%	N	%	N	%	N	%	N	%
Overall	2,080	3.6	1,848	3.2	2,109	3.7	2,905	5.1	2,572	4.5	2,664	4.6
Types of Chronic Conditions***
None***	332	1.3	326	1.3	433	1.7	660	2.6	437	1.7	488	1.9
CM only**	964	4.4	874	4.0	942	4.3	1,311	6.0	1,203	5.5	1,220	5.6
MH only**	24	3.0	21	2.6	34	4.2	29	3.6	30	3.7	30	3.7
RESP only**	71	3.1	49	2.2	58	2.5	96	4.2	72	3.2	68	3.0
CM + MH**	98	8.5	74	6.4	86	7.5	116	10.1	101	8.8	102	8.9
CM + RESP**	478	9.3	415	8.1	468	9.2	579	11.3	601	11.8	639	12.5
All Three***	113	18.4	89	14.5	88	14.3	114	18.6	128	20.8	117	19.1

Notes: Based on 57,489 elderly men, aged 67 years and older, diagnosed with incident prostate cancer between 2002 and 2009 and alive throughout the observation period. Significant differences in NCHs over time were tested with Wald chi-square, after accounting for correlations due to repeated measures. % represented in the column are column percentage.

Abbreviations: CM: Cardio-metabolic conditions; MH: Mental illness; RESP: Respiratory conditions;

^***p < .001;

^**.001 ≤ p < .01;

^*.01 ≤ p < .05

Table 3 displays the ORs and AORs and 95% confidence intervals (CI) using the unadjusted (Model I) and adjusted GEE models (Models II and III) on NCHs with exchangeable correlation structures. The model I revealed that elderly men were 37% more likely to have NCHs during the post-cancer period as compared to pre-cancer period (OR: 1.37, 95% CI: 1.32, 1.41). In model II, with adjustments for only the types of chronic conditions, elderly men were 38% more likely to have NCHs during post-cancer period (AOR: 1.38, 95% CI: 1.33, 1.42) as compared to the pre-cancer period., In model III, which controlled for all the independent variables, elderly men were 38% more likely to have NCHs during the post-cancer period as compared to the pre-cancer period.

Table 3.

Adjusted Odds Ratios and 95% Confidence Intervals (CI) of Cancer Diagnosis Period From GEE models on Non-Cancer Related Hospitalizations Elderly Men with Incident Prostate Cancer Surveillance, Epidemiology and End Results (SEER)-Medicare Linked Database-2000–2010

Model 1, adjusting for pre- and post-cancer period
	OR	95% CI	Sig.
Variable
Pre-cancer	Ref
Post-cancer	1.37	[1.32,1.41]	***
Model 2, adjusting for pre- and post-cancer period + Types of Chronic Conditions
	AOR	95% CI	Sig.
Pre-cancer	Ref
Post-cancer	1.38	[1.33,1.42]	***
Model 3, adjusting for pre- and post-cancer period + Types of Chronic Conditions + predisposing, enabling, need, and external environment characteristics
	AOR	95% CI	Sig.
Pre-cancer	Ref
Post-cancer	1.38	[1.33, 1.43]	***

Notes: Based on 57,489 elderly men, aged 67 years and older, diagnosed with incident prostate cancer between 2002 and 2009 and alive throughout the observation period. Significant differences are based on the log-likelihood test using a repeated measure generalized estimating equations. Model 3 adjusted for predisposing (age, race, and marital status), enabling status (quartile of median census 2000 income, quartile of median census 2000 education, and cancer treatment), external environment (region, quartile of radiation oncology, and quartile of urology centers) and need characteristics (number of other chronic conditions and T-stage).

AOR: Adjusted Odds Ratio; GEE: Generalized Estimating Equation; AOR: Adjusted Odds Ratio; Sig: Level of Sig: Significance.

^***p < .001;

^**.001 ≤ p < .01;

^*.01 ≤ p < .05

Probabilities of NCHs by Pre and Post-Cancer Period

Table 4 displays the probabilities of NCHs by the pre-and post-cancer period for the types of chronic conditions. Based on the fully adjusted model (Model III), an increase in the probability of NCHs was observed for the post cancer period (p = 0.027) as compared to pre-cancer period (probabilities, p: 0.028 vs. 0.036, change in p = .009). Elderly men with all the three types of chronic conditions had the greatest increase in the probabilities of NCHs during post cancer period (p: 0.141) as compared to pre-cancer period (p: 0.107), whereas, elderly men with none of the types of chronic conditions had the lowest change in the probabilities of NCHs (p: 0.021) during post-cancer period as compared to pre-cancer period (p: 0.016).

Table 4.

Predicted Probabilities with 95% Confidence Intervals for Types of Chronic Conditions From GEE analysis on Non-Cancer Related Hospitalizations Elderly Medicare Beneficiaries with Incident Prostate Cancer Surveillance, Epidemiology and End Results (SEER)-Medicare Linked Database-2000–2010

	Pre-cancer		Post-cancer		Changes in	Additive
	P	95% CI	P	95% CI	Probabilities	Effect
Model 1, adjusted for pre- and post-cancer period
Overall***	0.035	[0.034, 0.036]	0.047	[0.046, 0.048]	0.012
Model 2, adjusted for pre- and post-cancer period + Types of Chronic Conditions
Overall***	0.028	[0.027,0.029]	0.038	[0.037, 0.039]	0.010
Types of Chronic Conditions***
None	0.018	[0.017, 0.018]	0.031	[0.030, 0.032]	0.013	Ref
CM only	0.044	[0.043, 0.046]	0.077	[0.075, 0.079]	0.033	0.020
MH only	0.032	[0.027, 0.037]	0.055	[0.047, 0.063]	0.023	0.010
RESP only	0.029	[0.026, 0.031]	0.05	[0.045, 0.054]	0.021	0.008
CM + MH	0.075	[0.069, 0.081]	0.127	[0.117, 0.137]	0.052	0.039
CM + RESP	0.087	[0.084, 0.091]	0.146	[0.141, 0.151]	0.059	0.046
All Three	0.150	[0.138, 0.162]	0.239	[0.222, 0.256]	0.089	0.076
Model 3 adjusted for pre- and post-cancer period + Types of Chronic Conditions + predisposing, enabling, need, and external environment characteristics
Overall***	0.027	[0.026, 0.028]	0.036	[0.036, 0.038]	0.009
Types of Chronic Conditions***
None	0.016	[0.015, 0.016]	0.021	[0.020, 0.022]	0.008	Ref
CM only	0.039	[0.038, 0.041]	0.053	[0.052, 0.055]	0.014	0.008
MH only	0.026	[0.022, 0.030]	0.036	[0.030, 0.041]	0.010	0.004
RESP only	0.021	[0.019, 0.023]	0.029	[0.026, 0.032]	0.008	0.002
CM + MH	0.056	[0.051, 0.061]	0.075	[0.069, 0.082]	0.020	0.014
CM + RESP	0.066	[0.062, 0.069]	0.088	[0.084, 0.092]	0.023	0.017
All Three	0.107	[0.097, 0.116]	0.141	[0.129, 0.153]	0.035	0.029

Notes: Based on 57,489 elderly men, aged 67 years and older, diagnosed with incident prostate cancer between 2002 and 2009 and alive throughout the observation period. Significant differences are based on the log-likelihood test using a repeated measure generalized estimating equations. Model 3 adjusted for predisposing (age, race, and marital status), enabling status (quartile of median census 2000 income, quartile of median census 2000 education, and cancer treatment), external environment (region, quartile of radiation oncology, and quartile of urology centers) and need characteristics (number of other chronic conditions and T-stage).

Abbreviations: CM: Cardio-metabolic conditions; MH: Mental health conditions; RESP: Respiratory conditions; Sig: Level of Significance;

^***p < .001;

^**.001 ≤ p < .01;

^*.01 ≤ p < .05

DISCUSSION

Till date, the current study is the only largest population-based cohort that examined the risk of NCHs before and after the diagnosis of prostate cancer among elderly men with incident prostate cancer. We observed many noteworthy findings, which have implications for the better management of pre-existing chronic conditions among men with incident prostate cancer.

Elderly men with incident prostate cancer had a higher risk of NCHs during the post-cancer period as compared to the pre-cancer period, even after controlling for a comprehensive list of risk factors. A closer examination of the rates of hospitalizations over six time periods suggested that the highest rates of NCHs occurred during first four months after the cancer diagnosis. There are several plausible explanations for this increased risk. It has been documented that the diagnosis of prostate cancer, by itself, can trigger psychological distress, anxiety and suicidal ideations (39). The increase in the psychological stress may increase the blood levels of epinephrine and norepinephrine resulting in increased heart rate, blood pressure and levels of blood sugars. In fact, studies have shown that acute psychological stress may lead to stimulate inflammatory markers such as interleukins, sex hormones and cortisol levels, which may precipitate into serious conditions such as heart disease (24). Our study findings by types of chronic conditions, we found that those with cardio-metabolic conditions alone or combinations of cardio-metabolic conditions with respiratory or mental health conditions had a greater increase in the risk of NCHs during the post-cancer period as compared to the pre-cancer period. Previous literature suggests that elderly men with pre-existing cardio-metabolic conditions may experience acute emotional or psychological stress, which may trigger incidence of another heart failure episode (25, 26), leading to hospitalizations. It has to be noted that the current study did not include newly-diagnosed chronic conditions, therefore, increased hospitalizations during the post-cancer period for this group may suggest the worsening of pre-existing cardio-metabolic conditions due to prostate cancer diagnosis.

The current study is one of the very few studies to explore the trajectory of non-cancer outcomes (i.e. hospitalizations) during the pre-cancer and post-cancer period among fee-for-service Medicare beneficiaries with incident localized prostate cancer using the cancer registry-linked administrative claims data. The study findings reinforce the need for intervention to reduce the NCHs among elderly men with incident prostate cancer. Among elderly men with prostate cancer, the risk of NCH was higher during the year subsequent to prostate cancer diagnosis as compared to the year before prostate cancer diagnosis. These findings highlight the need for targeted research, program, policy, and intervention efforts to reduce the excess NCHs in this group. As appropriate management of pre-existing chronic conditions is key to reducing the risk of NCH, effective communication between the oncologists and primary care physicians should be facilitated so to implement an individualized care plan and provide patient education. Elderly men with cardio-metabolic conditions alone and those with a combination of cardio-metabolic and respiratory or mental health conditions were most vulnerable to an increased risk of NCH. In this regard, optimizing care in the clinical settings by focusing on the “ABCS” (aspirin when appropriate, blood pressure control, cholesterol management, and smoking cessation) can help reduce the risk of NCH (27). A mid-year review by the national Million Hearts initiative, which was launched in 2012, suggests some success in reducing the risk of NCH (28). However, the current study findings need to be interpreted in the context of its limitations. Although, due diligence was given in measuring NCHs based on previously published studies, one cannot rule out the possibility that some NCHs may be due to cancer treatment i.e. sepsis due to surgery.

CONCLUSION

Diagnosis of incident prostate cancer was associated with an increase in the risk of NCHs among elderly men with incident localized prostate cancer. Future research needs to examine whether better management strategies for cardio-metabolic and other chronic conditions can reduce the increased risk for NCHs after the diagnosis of prostate cancer.