Racial and Gender Disparities in different regions of the United States in patients with metastatic lung and bronchial cancer

doi:10.21203/rs.3.rs-1602587/v1

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Racial and Gender Disparities in different regions of the United States in patients with metastatic lung and bronchial cancer

https://doi.org/10.21203/rs.3.rs-1602587/v1

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Background: Lung Cancer is the leading cause of cancer deaths in the US, making up almost a quarter of all cancer deaths. Disparities exist upon closer examination: African American (AA) males were found to have a higher incidence of developing lung cancer compared to their Caucasian counterparts. Some plausible reasons for higher incidence rates in AA patients may be due to differences in smoking habits, socioeconomic variables, and metabolism of tobacco carcinogens. Along with these factors, societal differences and lack of resources are postulated to play a significant role. These differences were also observed in clinical trials with an underrepresentation of minorities. A niche deficit exists in outcomes of racial minorities with metastatic lung and bronchial cancer.

Methods: Data for this study was obtained from the 2016-18 Nationwide Inpatient Sample (NIS). This is maintained as part of the Health Care Utilization Project (HCUP) of the Agency for Healthcare Research and Quality (AHRQ). It is the largest all-payer inpatient care database in the US and comprises a 20% stratified random sample of all US hospital discharges. Further details: https://www.hcup-us.ahrq.gov/

Results: We identified 238,516 patients with Metastatic Lung and bronchial cancer, of which 77.45% were Caucasians, 12.48% AAs, 4.74% Hispanics, and 2.81 % Asians and Pacific Islanders (API). Almost 40% of the study population is from the Southern region, followed by 24.25% in Midwest, 20.56% in the Northeast, and 14.81% in the West. Other race populations had the most reported deaths (10.42%), followed by APIs (10.30%), Native Americans (8.67%), Hispanics (8.75%), AAs (8.66%), and Caucasians (8.34%) (p <0.000). AAs had significantly higher deaths in the South (17.24%) and APIs had significantly higher deaths in the West (12.21%) compared to other regions (p <0.0001). With and without adjusting all the other variables, AAs (OR = 1.069 (1.046 - 1.091)), APIs (OR = 1.230 (1.184 - 1.278)), Native Americans (OR = 1.207 (1.091 - 1.336)), and Others (OR = 1.300 (1.250 - 1.351)) have significantly higher odds of dying when compared to Caucasians.The odds of all-cause mortality for African Americans and Asians and Pacific Islanders remain higher in comparison in all the regions.

Conclusions: Racial minorities remain at higher odds of all-cause mortality in all regions, and focused programs to improve their access to healthcare, insurance and resources should help alleviate these disparities.

Racial disparities

gender disparities

Lung Cancer

African Americans

Caucasians

Asian and Pacific Islanders

regional variation

all-cause mortality

Lung Cancer is one of the most common causes of cancer deaths in the US, with a 5-year survival of 19%.[1] African American males were found to have a higher incidence of developing lung cancer compared to white males. [2] According to Gadgeel et al. reason for higher lung cancer incidence rates in blacks may be due to racial differences in smoking habits, socioeconomic variables, and the metabolism of tobacco carcinogens. [3] Along with this, societal differences and lack of resources must be playing a significant role. It is seen that racial differences are seen in the clinical trials as well, where minorities are underrepresented, which further leads to decreased survival in minorities.[4] According to Yang R. et al., it was seen that when adjusting for demographics and comorbidities, being African American is not a statistically significant predictor of worse outcomes.[5] Here, in our study, we aim to evaluate any racial or gender differences in different regions of the US in deaths of patients with metastatic lung or bronchial cancer.

Data for this study was obtained from the 2016-18 Nationwide Inpatient Sample (NIS). The NIS is maintained as part of the Health Care Utilization Project (HCUP) of the Agency for Healthcare Research and Quality (AHRQ). It is the largest all-payer inpatient care database in the US and comprises a 20% stratified random sample of all US hospital discharges. Each discharge in the NIS is de-identified, so all discharges were considered to be independent. The unit for this analysis was each discharge rather than each individual. Further details on the NIS design are available at https://www.hcup-us.ahrq.gov/ .

Study Population:

We identified all patients with a primary diagnosis of Malignant Neoplasms of Lungs and Bronchus by querying the database using the International Classification of Disease-Clinical Modification, 10th revision (ICD-10 CM) code “C34”.

Study Variables:

The ICD 10 CM codes were used to find other variables, which are mentioned in Table 1. In-hospital mortality, race, and hospital regions were studied using HCUP variables named “DIED,” “Race,” and “HOSP_REGION,” respectively.

Table 1

Variables Used
ICD 10 Codes	Diagnoses
C34	Malignant Neoplasms of Lungs and Bronchus
Z720	Smoking
Z5111	Chemotherapy
Z5112	Immunotherapy
Z510	Radiation
Z515	Palliative Care

Aims and objectives:

Our study’s main aim was to study racial disparity in all-cause mortality in patients with metastatic neoplasms of lungs and bronchus. Our secondary goal was to evaluate the racial and gender gap in all-cause mortality in patients with malignant neoplasms of lungs and bronchus in different regions of the USA.

Statistical analysis:

We used SAS 9.4 (SAS Institute Inc, Cary, North Carolina) for data analysis. Categorical variables and continuous variables were assessed by the Rao Scott Chi-square test and the Pooled t-test, respectively. A two-tailed alpha of < 0.05 was required for statistical significance. Baseline characteristics of participants were summarized using descriptive statistics. Logistic regression was performed to derive the odds ratio while adjusting for different variables. The modified Charlson Comorbidity Index (CCI), a validated weighted comorbidities disease severity score composed of 17 comorbid conditions, was calculated for all participants.

We identified 238,516 patients with Metastatic Lung and bronchial cancer. 51.15% were males, and 48.85% were females, with a mean age of 69.02 years. 77.45% of the population was Caucasians, 12.48% African Americans, 4.74% Hispanics, and 2.81% Asians and Pacific Islanders. Almost 40% of the study population is from the Southern region, followed by 24.25% in Midwest, 20.56% in the Northeast, and 14.81% in the West. With the study’s limitations, we could not gather the exact number of patients receiving treatment for metastatic lungs and bronchial cancers. It was seen that 0.68% of patients were on chemotherapy, 0.22% received radiation therapy, and 0.01% were on immunotherapy. 14.74% of patients were given palliative treatment. (Table 2)

Table 2

demographic of the population
variables		Total (N (%))	Died (N (%))		p-value
variables		Total (N (%))	Yes	No	p-value
Age (Mean)		69.02 ± 10.68	69.58 ± 10.63	68.96 ± 10.69	< 0.0001
Race	White	179,518 (77.45)	14,966 (8.34)	164,552 (91.66)	< 0.0001
	African American	28,936 (12.48)	2,505 (8.66)	26,431 (91.34)
	Hispanic	10,979 (4.74)	961 (8.75)	10,018 (91.25)
	Asian and Pacific Islanders	6,508 (2.81)	670 (10.30)	5,838 (89.70)
	Native Americans	865 (0.37)	75 (8.67)	790 (91.33)
	Others	4,982 (2.15)	519 (10.42)	4,463 (89.58)
Hosp Region	Northeast	49,001 (20.56)	4,369 (8.92)	44,632 (91.08)	< 0.0001
	Midwest	57,786 (24.25)	4,450 (7.70)	53,336 (92.30)
	South	96,252 (40.39)	7,994 (8.30)	88,258 (91.69)
	West	35,290 (14.81)	3,522 (9.98)	31.768 (90.02)
Gender	Female	116,367 (48.85)	9,020 (7.75)	107,347 (92.25)	< 0.0001
Gender	Male	121,849 (51.15)	11,309 (9.28)	110,540 (90.72)	< 0.0001
Smoking	Yes	3,335 (1.40)	258 (7.74)	3,077 (92.26)	0.0974
Smoking	No	234,994 (98.60)	20,077 (8.54)	214,917 (91.46)	0.0974
Chemotherapy	Yes	1,630 (0.68)	49 (3.01)	1,581 (96.99)	< 0.0001
Chemotherapy	No	236,699 (99.32)	20,286 (8.57)	216,413 (91.43)	< 0.0001
Immunotherapy	Yes	24 (0.01)	1 (4.17)	23 (95.83)	0.4439
Immunotherapy	No	238,305 (99.99)	20,334 (8.53)	217,971 (91.47)	0.4439
Radiation Therapy	Yes	538 (0.22)	27 (5.02)	511 (94.98)	0.0035
Radiation Therapy	No	237,791 (99.77)	20,308 (8.54)	217,483 (91.46)	0.0035
Palliative Care	Yes	35,126 (14.74)	10,917 (31.08)	24,209 (68.92)	< 0.0001
Palliative Care	No	203,203 (85.26)	9,418 (4.64)	193,785 (95.36)	< 0.0001
Charlson (Mean)		12.82 ± 1.54	12.61 ± 1.54	12.87 ± 1.54	0.1106

In terms of all-cause mortality, the older population (69.58 ± 10.63 vs. 68.96 ± 10.69, p < 0.0001) and males were more likely to die (9.28% vs. 7.75%, p < 0.0001). Other race populations had the most death (10.42%), followed by Asians and Pacific Islanders (10.30%), Native Americans (8.67%), Hispanics (8.75%), African Americans (8.66%), and Caucasians (8.34%) (p < 0.0001). Most deaths were seen in the West region (9.98%), followed by Northeast (8.92%), South (8.30%), and the least in Midwest (7.70%) (p < 0.0001). Patients who received chemotherapy and radiation therapy were having lesser deaths when compared to patients who didn’t receive the treatment (3.01% vs. 8.57 for chemotherapy, p < 0.0001, and 5.02% vs. 8.54% for radiation therapy, p = 0.0035). Though not significant, lesser deaths were seen in the immunotherapy group (4.17% vs. 8.53%, p = 0.4439). Charlson Comorbidity index difference was not statistically significant in both groups (12.61 ± 1.54 vs 12.87 ± 1.54, p = 0.1106). (Table 2)

When looking into different regions, it is seen that a significantly younger population died in the South (68.79 ± 10.59 years) compared to other regions (p < 0.0001). Overall, Caucasians died the most in all the regions, but African Americans had significantly higher deaths in the South (17.24%) and Asians and Pacific Islanders had significantly higher deaths in the West (12.21%) compared to other regions (p < 0.0001). There was no significant difference between deaths of males or females in all the regions (p = 0.1706). There was no statistical difference in Charlson Comorbidity Index as well in different regions. (p = 0.8177). (Table 3)

Table 3

Demographics of Lung Cancer Death according to geographic location
Variable		Hospital region (N (%))				p-value
Variable		Northeast	Midwest	South	West	p-value
Age (Means)		70.53 ± 10.66	69.47 ± 10.46	68.79 ± 10.59	70.37 ± 10.74	< 0.0001
Race	White	3,387 (78.53)	3,497 (84.12)	5,721 (73.10)	2,361 (69.44)	< 0.0001
	African American	444 (10.29)	505 (12.15)	1,349 (17.24)	207 (6.09)
	Hispanic	171 (3.96)	60 (1.44)	425 (5.43)	305 (8.97)
	Asian and Pacific Islanders	119 (2.76)	42 (1.01)	94 (1.2)	415 (12.21)
	Native Americans	4 (0.09)	16 (0.38)	32 (0.4)	23 (0.68)
	Others	188 (4.36)	37 (0.89)	205 (2.62)	89 (2.62)
Gender	Male	2,405 (55.06)	2,441 (54.87)	4,523 (56.59)	1,940 (55.11)	0.1706
Gender	Females	1,963 (44.94)	2,008 (45.13)	3,469 (43.41)	1,580 (44.89)	0.1706
Smoking		37 (14.34)	56 (21.70)	114 (44.19)	51 (19.77)	0.0336
Chemotherapy		7 (14.29)	10 (20.41)	27 (55.10)	5 (10.20)	1.225
Immunotherapy		0	0	0	1	-
Radiation Therapy		4 (14.82)	12 (44.44)	6 (22.22)	5 (18.52)	0.0309
Palliative Care		2,387 (21.86)	2,544 (23.30)	3,937 (36.06)	2,049 (18.77)	< 0.0001
Charlson (Means)		12.36 ± 1.47	12.80 ± 1.61	12.64 ± 1.67	12.62 ± 1.41	0.8177

As seen in Table 4, the odds ratio was calculated for all-cause mortality and different variables. It is evident that receiving any form of treatment in terms of chemotherapy, immunotherapy, and radiation therapy decreased the odds of all-cause mortality significantly. Being female decreases the odds of all-cause mortality overall as well as in all the regions when compared to males (OR = 0.788), but odds of dying are significantly more for females in the West when compared to females in the Northeast (OR = 1.032 (1.001–1.063)). Males have lower odds of dying in the Midwest (OR = 0.861 (0.838–0.886)) and South (OR = 0.951 (0.929–0.974)) regions, and no statistical difference in West (OR = 1.028 (1.000–1.056)) when compared to the Northeast.

Table 4

Demonstrating Odds Ratio for dying
Variable		Odds Ratio
		Unadjusted	Adjusted^a	Gender^b		Hospital Region^b
		Unadjusted	Adjusted^a	Male	Female	Northwest	Midwest	South	West
Gender when compared to males	Females	0.788 (0.777–0.799)	0.786 (0.775–0.797)	-	-	0.807 (0.784–0.830)	0.824 (0.800–0.849)	0.798 (0.781–0.816)	0.801 (0.778–0.825)
Hospital Region when compared to Northeast	Midwest	0.820 (0.803–0.838)	0.824 (0.806–0.842)	0.861 (0.838–0.886)	0.883 (0.857–0.910)	-	-	-	-
	South	0.924 (0.907–0.941)	0.918 (0.901–0.935)	0.951 (0.929–0.974)	0.956 (0.932–0.982)	-	-	-	-
	West	0.989 (0.968–1.010)	0.975 (0.954–0.996)	1.028 (1.000–1.056)	1.032 (1.001–1.063)	-	-	-	-
Race when compared to whites	African American	1.052 (1.030–1.074)	1.069 (1.046–1.091)	1.137 (1.106–1.168)	1.099 (1.069–1.130)	1.159 (1.110–1.209)	1.091 (1.044–1.140)	1.117 (1.086–1.148)	1.077 (1.013–1.144)
	Hispanic	0.990 (0.964–1.016)	0.994 (0.968–1.020)	1.019 (0.985–1.054)	0.970 (0.936–1.007)	0.942 (0.886–1.001)	0.930 (0.846–1.023)	0.958 (0.921–0.997)	1.025 (0.983–1.069)
	Asian and Pacific Islanders	1.222 (1.177–1.269)	1.230 (1.184–1.278)	1.344 (1.281–1.410)	1.186 (1.126–1.250)	1.154 (1.065–1.252)	1.182 (1.041–1.342)	1.226 (1.119–1.344)	1.260 (1.201–1.321)
	Native Americans	1.199 (1.084–1.327)	1.207 (1.091–1.336)	1.160 (1.013–1.328)	1.365 (1.195–1.560)	0.570 (0.341–0.953)	0.975 (0.753–1.263)	1.379 (1.177–1.616)	1.374 (1.195–1.580)
	Others	1.296 (1.247–1.347)	1.300 (1.250–1.351)	1.159 (1.103–1.218)	1.260 (1.195–1.329)	1.368 (1.287–1.455)	0.994 (0.871–1.135)	1.043 (0.984–1.105)	1.310 (1.205–1.424)
Palliative Care^a		15.323 (15.102–15.546)
Chemotherapy^a		0.284 (0.262–0.308)
Radiation Therapy^a		0.416 (0.313–0.553)
Immunotherapy^a		0.326 (0.199–0.533)
Smoking^a		0.945 (0.871–1.026)
^a Adjusted for age, race, gender, hospital region, immunochemotherapy, radiation therapy, smoking, and palliative therapy ^b Adjusted for Age, Race, Hospital region

With and without adjusting all the other variables, African Americans (OR = 1.069 (1.046–1.091)), Asians and Pacific Islanders (OR = 1.230 (1.184–1.278)), Native Americans (OR = 1.207 (1.091–1.336)), and Others (OR = 1.300 (1.250–1.351)) have significantly higher odds of dying when compared to Caucasians; while Hispanics (OR = 0.994 (0.968–1.020)) have no statistical difference, which remains unchanged in either gender. The odds of all-cause mortality for African Americans and Asians and Pacific Islanders remain high in all the regions compared to Caucasians. Hispanics have significantly lower odds of all-cause mortality compared to Caucasians in the Southern region (OR = 0.958 (0.921–0.997)), and no statistical difference in other regions. Native Americans (OR = 0.570 (0.341–0.953)) have lower odds of dying in the Northeast, no statistical difference (OR = 0.975 (0.753–1.263)) in the Midwest, and higher in the South and the West. Races other than the above had no statistical difference in odds of all-cause mortality in the Midwest and the South when compared to Caucasians, but had higher odds in the Northeast and the West.

We observed decreased odds of death associated with female gender, regardless of the region. Amongst these regions, the odds of females dying in the West were more than the odds of females dying in the Northeast. This is in contrast to the national life expectancy data, where western states were amongst the top life expectancy states for both men and women. [6] Interestingly, this trend did not reflect in the male subset of our patients. Males, on the other hand, had decreased odds of dying in the Midwest and the South when compared to the Northeast, concurrent with the general overall life expectancy data. These disparities may in part be explained by differences in habits including smoking, lifestyles and the environment. Freeman et al noted the incidence rates of lung cancer in never smokers were significantly higher in women (25.3 (21.3–29.3)) versus men (20.3 (16.3–24.3)). [12, 13] While comparing the incidence rates in smokers as well, they noticed higher incidence rates in current women smokers of more than 40 cigarettes per day, but lower rates compared to men when smoking 30 cigarettes per day, raising the question of epigenetics and susceptibility to tobacco carcinogens, subtypes of lung cancer affecting both genders, early screening, etc.

As seen in multiple studies done in the past, African Americans tend to have higher odds of all-cause mortality in all the regions. [2, 5, 7] This could be also a result of the decline in treatment which is more often seen in African Americans, especially seen in a study where Blacks were declining a procedure more often than Whites.[8] Another large study exploring disparities in cancer care demonstrates the largest noted disparity, of about 15%, between AA and Caucasian men with early-stage lung cancer undergoing surgical resection (76% vs 60%). The same study demonstrated AA population was significantly more likely to reside in areas of low median income and have no documented physician visits. [9] Other minorities have not been studied well in the literature, but it is seen in some studies that Hispanics and American Indians have a lower incidence of mortality compared to Caucasians.[2] A plausible explanation is the prevalence of smoking in each population subset. Caucasians and African-Americans have a significantly higher smoking prevalence than other ethnic groups in the USA, and Hispanics have a much lower prevalence, which is reflected in lung cancer mortality data as well. The strongest risk factor for lung cancer, cigarette smoking, and the most important determinant of lung cancer mortality, advanced stage at diagnosis, are both more prevalent in AAs compared to Caucasians. [10] Our study shows that Hispanics have lower odds of all-cause mortality only in the Southern region, while no statistical difference is seen in the other regions. Asians and Pacific Islanders had higher odds of all-cause mortality in all the regions, while Native Americans had significantly lower odds of death in the Northeast when compared to Caucasians, but significantly higher odds in the South and the West. In a study based on outcomes in early-stage lung cancer, it was noted that Asians had better survival and lower deaths compared to Caucasians.[11] Our study, though not commenting on the stage of cancer, shows increased odds of all-cause mortality in Asians and Pacific Islanders.

Although the disparities between AA men and Caucasian men continue to trend down (33.8% in 2000 to 22.9% in 2010) over the years, they remain persistently higher in AA men to date. (73.6 deaths vs 59.9 deaths in 2010). [10] Improving access to healthcare, knowledge, close primary care follow ups with stress on nicotine cessation, and access to Medicaid/Medicare insurances along with special attention to certain races in particular regions will help in decreasing the all-cause mortality in metastatic lung cancer. Our study does provide knowledge in gender and racial disparity occurrence in the different areas, which is beneficial in a variety of areas, including, but not limited to, offering screening tests, smoking cessation, the possibility of incorporating appropriate races for clinical trials in particular regions, etc.

The limitations in our study are associated with administrative claims data, which contains codes produced for billing and documentation purposes. Being a retrospective study, we can only report an association between races and all-cause mortality in lung cancer patients. In-depth research is required to check whether race and gender differences do occur in different regions. Since ICD-10-CM codes were used to identify all the diagnoses and associated comorbid conditions, the possibility of coding errors cannot be overlooked.

Racial and gender differences occur in all-cause mortality in patients with metastatic lung and bronchial cancer in different regions. This may be related to the occurrence of cancer and other comorbidities. Even on adjusting the comorbidities, it was seen that racial differences are there in different regions. Extra attention needs to be paid in these races depending on the region.

Acknowledgements:

none

Disclaimers:

none

Competing Interests:

The authors have no relevant financial or non-financial interests to disclose.

Author Contributions:

All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Devashish Desai. The first draft of the manuscript was written by Devashish Desai and Sachi Singhal, and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

Data Availability:

The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.

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Racial and Gender Disparities in different regions of the United States in patients with metastatic lung and bronchial cancer

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Abstract

Introduction

Methods

Study Population:

Study Variables:

Aims and objectives:

Statistical analysis:

Results

Discussion

Conclusion

Declarations

References

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