Letters to the Editor
nature publishing group
How Does Length of Stay in the United States Affect Colorectal Cancer Incidence Among Immigrant Asian Populations in California? Phani K. Molakatalla, MD, MPH1 and Anand R. Kumar, MD, MPH1 doi:10.1038/ajg.2014.248
To the Editor: Ladabaum et al. (1) described the variation in colorectal cancer (CRC) incidence rates among Asian subgroups in California, in relation to nativity, socioeconomic status (SES), and residence in ethnic enclave. Incidence was significantly different among the subgroups and was inversely associated with the level of “ethnic enclave” among Asians. The authors concluded that acquired environmental factors significantly affected CRC incidence. However, an important question remains unanswered. How long do Asian immigrants need to be exposed to these environmental factors before their CRC risk increases? In other words, how does the length of stay in the United States affect CRC incidence among Asian immigrants? The current study (1) attempts to dissect the genetic and environmental interactions in CRC causation. McMichael et al. (2) reported that immigrants who resided longer in Australia had CRC mortality rates approaching that of the native population. This change was more evident after residing in Australia for 16 years. Mexicans migrating as children to Los Angeles were noted by Mack et al. (3) to have higher incidence rates of CRC compared with adults. These studies were reported decades ago and did not factor in the increasing CRC incidence in the general population during those years. The duration of exposure to the environment could be a key factor in raising an individual’s CRC risk. In the current study (1), the authors seem to have the data on the age © 2014 by the American College of Gastroenterology
at which an Asian immigrant obtained the social security number. These data may be used as a surrogate measure for the number of years in the United States. Moreover, given the size of the study sample, relationship between the duration of stay in the United States and CRC risk among Asian immigrants can be established after adjusting for potential confounders. The current study (1) examines the influence of various environmental factors traditionally known to affect CRC incidence in a more structured manner. Can the authors provide more information on the duration of stay of Asian immigrants in the United States and its association with the risk for colorectal cancer?
Drs Molakatalla and Kumar (1) are correct that we have available data on the age at receipt of a social security number for persons diagnosed with colorectal cancer, and that this could serve as a lower bound estimate for time of immigration to the United States. These persons constitute the numerators in incidence calculations. Unfortunately, we do not have such data for the cohorts at risk—that is, the populations of immigrants that constitute the denominators. Without these, we are unable to calculate incidence rates adjusted for length of stay in the United States. We agree with Drs Molakatalla and Kumar (1) that analyses that can address this important question would be of great interest.
CONFLICT OF INTEREST
The authors declare no conflict of interest.
CONFLICT OF INTEREST The authors declare no conflict of interest.
REFERENCES
REFERENCES
1. Ladabaum U, Clarke CA, Press DJ et al. Colorectal cancer incidence in Asian populations in California: effect of nativity and neighborhood-level factors. Am J Gastroenterol 2014;109:579–88. 2. McMichael AJ, Giles G G. Cancer in migrants to Australia: extending the descriptive epidemiological data. Cancer Res 1988;48:751–6. 3. Mack TM, Walker A, Mack W et al. Cancer in hispanics in Los Angeles county. Natl Cancer Inst Monogr 1985;69:99–104.
1. Molakatalla PK, Kumar AR. How does length of stay in the United States affect colorectal cancer incidence among immigrant Asian populations in California? Am J Gastroentrol 2014;109:1687 (this issue).
1
Einstein Medical Center, Department of Gastroenterology, Philadelphia, Pennsylvania, USA. Correspondence: Phani K. Molakatalla, MD, MPH, Einstein Medical Center, Department of Gastroenterology, 5401 Old york Road, Klein, Suite 363, Philadelphia, Pennsylvania 19141, USA. E-mail: [email protected]
Response to Molakatalla and Kumar 1, 2
Uri Ladabaum, MD, MS , Christina A. Clarke, PhD1,2, Iona Cheng, PhD1, 2 and Scarlett Lin Gomez, PhD1, 2
1
Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, California, USA; 2Cancer Prevention Institute of California, Fremont, California, USA. Correspondence: Uri Ladabaum, MD, MS, Division of Gastroenterology and Hepatology, Stanford University School of Medicine, 450 Broadway St, Pavillion C 4th Floor, MC: 6341, Redwood city, California 94063, USA. E-mail: [email protected]
Comment on Parikh et al. Ross A. Sage, MD1, Estela Mogrovejo, MD1, Atulkumar Patel, MD1 and Palaniappan Manickam, MD1 doi:10.1038/ajg.2014.252
doi:10.1038/ajg.2014.259
To the Editor: Drs Molakatalla and Kumar (1) raise an important point. It is reasonable to hypothesize that the risk of colorectal cancer in immigrants is associated with the length of stay in the United States.
To the Editor: We read with great interest the article by Parikh et al. (1). The authors performed a retrospective review comparing patients having an ERCP on a weekend or delaying it until Monday and found a significant difference in the length of stay The American Journal of GASTROENTEROLOGY
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Letters to the Editor
and a trend toward decreased cost associated with weekend ERCP. The aim of the study was focused on the length of stay and hospital costs. Previous studies have compared mortality after weekend vs. weekday admission showing evidence of a weekend effect for 7-day patient mortality. Previous studies have also shown an acute risk pattern to be consistent with a weekend effect. In the present study, this could have been obscured by the small sample size. In addition, this might have been better appreciated if the acuity of the problem would have been analyzed. It would have been interesting to see a comparison between indications such as stone decompression or elevated liver function tests (chronic conditions) compared with acute cholangitis (acute condition). In the presented study, the two most common diagnoses were choledocolithiasis and elevated liver function tests in post-transplant patients (35% and 25% of the cases, respectively), both accounting for 60% of the cases, which would have been classified as nonacute problems. With regard to Table 1 (baseline characteristics), within the “Procedure was emergent” group, this showed a P value less than 0.05. This suggests that the two variables (weekday and weekend) are significantly different to begin with, and this disparity possibly could have affected the results analysis. Patient baseline risk is another factor that could have been taken into consideration. Perez Concha et al. (2) concluded that patients admitted over the weekend had a lower baseline risk because they were younger and had less comorbidity; the explanation was that these patients are more likely to be employed and postpone seeking medical care. Finally, the presented study was conducted in a single tertiary academic center; results might not be applicable for smaller hospitals with a lower complexity of cases, low volume of patients, small number of endoscopists performing ERCPs, reduced number of staff and ancillary services, as well as private institutions where endoscopists and staff have different incentives and procedures have different costs. CONFLICT OF INTEREST The authors declare no conflict of interest. The American Journal of GASTROENTEROLOGY
nature publishing group
REFERENCES 1. Neehar D. Parikh, Rachel Issaka, Brittany Lapin et al. Inpatient weekend ERCP is associated with a reduction in patient length of stay. Am J Gastroenterol 2014;109:465–70. 2. Concha OP, Gallego B, Lapin B et al. Do variations in Hospital Mortality patterns after weekend admission reflect reduced quality of care or different patient cohorts? A population based study. BMJ Qaul Saf 2014;23:215–22. 1
Department of Gastroenterology, Beaumont Hospital, Royal Oak, Michigan, USA. Correspondence: Ross A. Sage, MD, Department of Gastroenterology, Beaumont Hospital, 3601W. Thirteen Mile Road, Royal Oak, Michigan 48073, USA. E-mail: [email protected]
Response to Sage and Mogrovejo Neehar D. Parikh, MD, MS1 and Rajesh Keswani, MD2 doi:10.1038/ajg.2014.257
To the Editor: We thank Dr Sage and Dr Mogrovejo for their thoughtful comments regarding our manuscript and the opportunity to clarify many of the points made in their comments (1). They correctly note that the focus of this study was to determine the effect on length of stay and costs when performing nonemergent procedures on weekends rather than a full analysis of the safety and outcomes of weekend procedures, which might require a larger sample size. However, the similarly low complication rates for both weekday and weekend procedures does suggest that performing weekend ERCPs with an experienced team is safe, in addition to being cost-effective. As expected, there is a significant difference in emergent procedures between the weekend and weekday cohorts, but this variable was included in our multivariate and propensity score analysis, and a significant difference remained between groups. To their next point regarding taking baseline risk of patients into account, we did this by taking several factors into account in our analysis, including ASA score, patient age, and indication for the procedure. We did not collect data to calcu-
late a formal comorbidity index. However, when we removed the post-liver transplant patients—who often have a high amount of comorbidity (Supplementary Table 2 online)—the subanalysis showed that significant differences remained between the weekend and weekday cohorts (1,2). With regard to their final point regarding the external validity of these findings, we fully acknowledge in our discussion that these findings may not be applicable to all healthcare settings, and they may not be logistically possible in many low resource areas. This study was conducted at a high ERCP volume academic center, with weekend procedures performed by one of three experienced on-call therapeutic endoscopists in conjunction with an experienced ERCP nurse and anesthesiologist. We contend that when appropriate resources are present to conduct weekend ERCPs hospital length of stay and costs will improve (3). We improved external validity through our subanalysis, but acknowledge that repeating the study in other healthcare settings would enhance the impact of our findings. In the 2001 Institute of Medicine report, “Crossing the Quality Chasm,” the following principles of achieving quality care were emphasized: safety, effectiveness, patientcenteredness, timeliness, efficiency, and equitability (4). Our study shows that performance of weekend ERCPs can improve the timeliness, efficiency, and, ultimately, patient-centeredness of inpatient care. We thank the authors for their thoughtful comments and appreciate the opportunity to clarify many of the points that have been made. CONFLICT OF INTEREST
The authors declare no conflict of interest.
REFERENCES 1. Parikh ND, Issaka R, Lapin B et al. Inpatient weekend ERCP is associated with a reduction in patient length of stay. Am J Gastroenterol 2014;109:465–70. 2. Jepsen P, Vilstrup H, Lash TL. Development and validation of a comorbidity scoring system for patients with cirrhosis. Gastroenterology 2014;146:147–56. 3. Polverejan E, Gardiner JC, Bradley CJ et al. Estimating mean hospital cost as a function of length of stay and patient characteristics. Health Econ 2003;12:935–47.
VOLUME 109 | OCTOBER 2014 www.amjgastro.com
nature publishing group
How Does Length of Stay in the United States Affect Colorectal Cancer Incidence Among Immigrant Asian Populations in California? Phani K. Molakatalla, MD, MPH1 and Anand R. Kumar, MD, MPH1 doi:10.1038/ajg.2014.248
To the Editor: Ladabaum et al. (1) described the variation in colorectal cancer (CRC) incidence rates among Asian subgroups in California, in relation to nativity, socioeconomic status (SES), and residence in ethnic enclave. Incidence was significantly different among the subgroups and was inversely associated with the level of “ethnic enclave” among Asians. The authors concluded that acquired environmental factors significantly affected CRC incidence. However, an important question remains unanswered. How long do Asian immigrants need to be exposed to these environmental factors before their CRC risk increases? In other words, how does the length of stay in the United States affect CRC incidence among Asian immigrants? The current study (1) attempts to dissect the genetic and environmental interactions in CRC causation. McMichael et al. (2) reported that immigrants who resided longer in Australia had CRC mortality rates approaching that of the native population. This change was more evident after residing in Australia for 16 years. Mexicans migrating as children to Los Angeles were noted by Mack et al. (3) to have higher incidence rates of CRC compared with adults. These studies were reported decades ago and did not factor in the increasing CRC incidence in the general population during those years. The duration of exposure to the environment could be a key factor in raising an individual’s CRC risk. In the current study (1), the authors seem to have the data on the age © 2014 by the American College of Gastroenterology
at which an Asian immigrant obtained the social security number. These data may be used as a surrogate measure for the number of years in the United States. Moreover, given the size of the study sample, relationship between the duration of stay in the United States and CRC risk among Asian immigrants can be established after adjusting for potential confounders. The current study (1) examines the influence of various environmental factors traditionally known to affect CRC incidence in a more structured manner. Can the authors provide more information on the duration of stay of Asian immigrants in the United States and its association with the risk for colorectal cancer?
Drs Molakatalla and Kumar (1) are correct that we have available data on the age at receipt of a social security number for persons diagnosed with colorectal cancer, and that this could serve as a lower bound estimate for time of immigration to the United States. These persons constitute the numerators in incidence calculations. Unfortunately, we do not have such data for the cohorts at risk—that is, the populations of immigrants that constitute the denominators. Without these, we are unable to calculate incidence rates adjusted for length of stay in the United States. We agree with Drs Molakatalla and Kumar (1) that analyses that can address this important question would be of great interest.
CONFLICT OF INTEREST
The authors declare no conflict of interest.
CONFLICT OF INTEREST The authors declare no conflict of interest.
REFERENCES
REFERENCES
1. Ladabaum U, Clarke CA, Press DJ et al. Colorectal cancer incidence in Asian populations in California: effect of nativity and neighborhood-level factors. Am J Gastroenterol 2014;109:579–88. 2. McMichael AJ, Giles G G. Cancer in migrants to Australia: extending the descriptive epidemiological data. Cancer Res 1988;48:751–6. 3. Mack TM, Walker A, Mack W et al. Cancer in hispanics in Los Angeles county. Natl Cancer Inst Monogr 1985;69:99–104.
1. Molakatalla PK, Kumar AR. How does length of stay in the United States affect colorectal cancer incidence among immigrant Asian populations in California? Am J Gastroentrol 2014;109:1687 (this issue).
1
Einstein Medical Center, Department of Gastroenterology, Philadelphia, Pennsylvania, USA. Correspondence: Phani K. Molakatalla, MD, MPH, Einstein Medical Center, Department of Gastroenterology, 5401 Old york Road, Klein, Suite 363, Philadelphia, Pennsylvania 19141, USA. E-mail: [email protected]
Response to Molakatalla and Kumar 1, 2
Uri Ladabaum, MD, MS , Christina A. Clarke, PhD1,2, Iona Cheng, PhD1, 2 and Scarlett Lin Gomez, PhD1, 2
1
Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, California, USA; 2Cancer Prevention Institute of California, Fremont, California, USA. Correspondence: Uri Ladabaum, MD, MS, Division of Gastroenterology and Hepatology, Stanford University School of Medicine, 450 Broadway St, Pavillion C 4th Floor, MC: 6341, Redwood city, California 94063, USA. E-mail: [email protected]
Comment on Parikh et al. Ross A. Sage, MD1, Estela Mogrovejo, MD1, Atulkumar Patel, MD1 and Palaniappan Manickam, MD1 doi:10.1038/ajg.2014.252
doi:10.1038/ajg.2014.259
To the Editor: Drs Molakatalla and Kumar (1) raise an important point. It is reasonable to hypothesize that the risk of colorectal cancer in immigrants is associated with the length of stay in the United States.
To the Editor: We read with great interest the article by Parikh et al. (1). The authors performed a retrospective review comparing patients having an ERCP on a weekend or delaying it until Monday and found a significant difference in the length of stay The American Journal of GASTROENTEROLOGY
1687
1688
Letters to the Editor
and a trend toward decreased cost associated with weekend ERCP. The aim of the study was focused on the length of stay and hospital costs. Previous studies have compared mortality after weekend vs. weekday admission showing evidence of a weekend effect for 7-day patient mortality. Previous studies have also shown an acute risk pattern to be consistent with a weekend effect. In the present study, this could have been obscured by the small sample size. In addition, this might have been better appreciated if the acuity of the problem would have been analyzed. It would have been interesting to see a comparison between indications such as stone decompression or elevated liver function tests (chronic conditions) compared with acute cholangitis (acute condition). In the presented study, the two most common diagnoses were choledocolithiasis and elevated liver function tests in post-transplant patients (35% and 25% of the cases, respectively), both accounting for 60% of the cases, which would have been classified as nonacute problems. With regard to Table 1 (baseline characteristics), within the “Procedure was emergent” group, this showed a P value less than 0.05. This suggests that the two variables (weekday and weekend) are significantly different to begin with, and this disparity possibly could have affected the results analysis. Patient baseline risk is another factor that could have been taken into consideration. Perez Concha et al. (2) concluded that patients admitted over the weekend had a lower baseline risk because they were younger and had less comorbidity; the explanation was that these patients are more likely to be employed and postpone seeking medical care. Finally, the presented study was conducted in a single tertiary academic center; results might not be applicable for smaller hospitals with a lower complexity of cases, low volume of patients, small number of endoscopists performing ERCPs, reduced number of staff and ancillary services, as well as private institutions where endoscopists and staff have different incentives and procedures have different costs. CONFLICT OF INTEREST The authors declare no conflict of interest. The American Journal of GASTROENTEROLOGY
nature publishing group
REFERENCES 1. Neehar D. Parikh, Rachel Issaka, Brittany Lapin et al. Inpatient weekend ERCP is associated with a reduction in patient length of stay. Am J Gastroenterol 2014;109:465–70. 2. Concha OP, Gallego B, Lapin B et al. Do variations in Hospital Mortality patterns after weekend admission reflect reduced quality of care or different patient cohorts? A population based study. BMJ Qaul Saf 2014;23:215–22. 1
Department of Gastroenterology, Beaumont Hospital, Royal Oak, Michigan, USA. Correspondence: Ross A. Sage, MD, Department of Gastroenterology, Beaumont Hospital, 3601W. Thirteen Mile Road, Royal Oak, Michigan 48073, USA. E-mail: [email protected]
Response to Sage and Mogrovejo Neehar D. Parikh, MD, MS1 and Rajesh Keswani, MD2 doi:10.1038/ajg.2014.257
To the Editor: We thank Dr Sage and Dr Mogrovejo for their thoughtful comments regarding our manuscript and the opportunity to clarify many of the points made in their comments (1). They correctly note that the focus of this study was to determine the effect on length of stay and costs when performing nonemergent procedures on weekends rather than a full analysis of the safety and outcomes of weekend procedures, which might require a larger sample size. However, the similarly low complication rates for both weekday and weekend procedures does suggest that performing weekend ERCPs with an experienced team is safe, in addition to being cost-effective. As expected, there is a significant difference in emergent procedures between the weekend and weekday cohorts, but this variable was included in our multivariate and propensity score analysis, and a significant difference remained between groups. To their next point regarding taking baseline risk of patients into account, we did this by taking several factors into account in our analysis, including ASA score, patient age, and indication for the procedure. We did not collect data to calcu-
late a formal comorbidity index. However, when we removed the post-liver transplant patients—who often have a high amount of comorbidity (Supplementary Table 2 online)—the subanalysis showed that significant differences remained between the weekend and weekday cohorts (1,2). With regard to their final point regarding the external validity of these findings, we fully acknowledge in our discussion that these findings may not be applicable to all healthcare settings, and they may not be logistically possible in many low resource areas. This study was conducted at a high ERCP volume academic center, with weekend procedures performed by one of three experienced on-call therapeutic endoscopists in conjunction with an experienced ERCP nurse and anesthesiologist. We contend that when appropriate resources are present to conduct weekend ERCPs hospital length of stay and costs will improve (3). We improved external validity through our subanalysis, but acknowledge that repeating the study in other healthcare settings would enhance the impact of our findings. In the 2001 Institute of Medicine report, “Crossing the Quality Chasm,” the following principles of achieving quality care were emphasized: safety, effectiveness, patientcenteredness, timeliness, efficiency, and equitability (4). Our study shows that performance of weekend ERCPs can improve the timeliness, efficiency, and, ultimately, patient-centeredness of inpatient care. We thank the authors for their thoughtful comments and appreciate the opportunity to clarify many of the points that have been made. CONFLICT OF INTEREST
The authors declare no conflict of interest.
REFERENCES 1. Parikh ND, Issaka R, Lapin B et al. Inpatient weekend ERCP is associated with a reduction in patient length of stay. Am J Gastroenterol 2014;109:465–70. 2. Jepsen P, Vilstrup H, Lash TL. Development and validation of a comorbidity scoring system for patients with cirrhosis. Gastroenterology 2014;146:147–56. 3. Polverejan E, Gardiner JC, Bradley CJ et al. Estimating mean hospital cost as a function of length of stay and patient characteristics. Health Econ 2003;12:935–47.
VOLUME 109 | OCTOBER 2014 www.amjgastro.com
