Optimizing the measurement of comorbidity for a South Australian colorectal cancer population using administrative data

Comorbidity Patterns in Patients Newly Diagnosed With Colorectal Cancer: Network-Based Study

BACKGROUND

Patients with colorectal cancer (CRC) often present with multiple comorbidities, and many of these can affect treatment and survival. However, previous comorbidity studies primarily focused on diseases in commonly used comorbidity indices. The comorbid status of CRC patients with respect to the entire spectrum of chronic diseases has not yet been investigated.

OBJECTIVE

This study aimed to systematically analyze all chronic diagnoses and diseases co-occurring, using a network-based approach and large-scale administrative health data, and provide a complete picture of the comorbidity pattern in patients newly diagnosed with CRC from southwest China.

METHODS

In this retrospective observational study, the hospital discharge records of 678 hospitals from 2015 to 2020 in Sichuan Province, China were used to identify new CRC cases in 2020 and their history of diseases. We examined all chronic diagnoses using ICD-10 (International Classification of Diseases, 10th Revision) codes at 3 digits and focused on chronic diseases with >1% prevalence in at least one subgroup (1-sided test, P<.025), which resulted in a total of 66 chronic diseases. Phenotypic comorbidity networks were constructed across all CRC patients and different subgroups by sex, age (18-59, 60-69, 70-79, and ≥80 years), area (urban and rural), and cancer site (colon and rectum), with comorbidity as a node and linkages representing significant correlations between multiple comorbidities.

RESULTS

A total of 29,610 new CRC cases occurred in Sichuan, China in 2020. The mean patient age at diagnosis was 65.6 (SD 12.9) years, and 75.5% (22,369/29,610) had at least one comorbidity. The most prevalent comorbidities were hypertension (8581/29,610, 29.0%; 95% CI 28.5%-29.5%), hyperplasia of the prostate (3816/17,426, 21.9%; 95% CI 21.3%-22.5%), and chronic obstructive pulmonary disease (COPD; 4199/29,610, 14.2%; 95% CI 13.8%-14.6%). The prevalence of single comorbidities was different in each subgroup in most cases. Comorbidities were closely associated, with disorders of lipoprotein metabolism and hyperplasia of the prostate mediating correlations between other comorbidities. Males and females shared 58.3% (141/242) of disease pairs, whereas male-female disparities occurred primarily in diseases coexisting with COPD, cerebrovascular diseases, atherosclerosis, heart failure, or renal failure among males and with osteoporosis or gonarthrosis among females. Urban patients generally had more comorbidities with higher prevalence and more complex disease coexistence relationships, whereas rural patients were more likely to have co-existing severe diseases, such as heart failure comorbid with the sequelae of cerebrovascular disease or COPD.

CONCLUSIONS

Male-female and urban-rural disparities in the prevalence of single comorbidities and their complex coexistence relationships in new CRC cases were not due to simple coincidence. The results reflect clinical practice in CRC patients and emphasize the importance of measuring comorbidity patterns in terms of individual and coexisting diseases in order to better understand comorbidity patterns.

Occurrence of comorbidity with colorectal cancer and variations by age and stage at diagnosis

BACKGROUND

While age and stage at diagnosis are known to affect treatment choices and survival from colorectal cancer (CRC), few studies have investigated the extent to which these effects are influenced by comorbidity. In this study, we describe the occurrence of comorbidity in CRC cases in South Australia and associations of comorbidity with age, stage and the age-stage relationship. Furthermore, we report on the association of individual comorbidities with age and stage at diagnosis.

METHODS

The South Australian Cancer Registry (SACR) provided CRC data (C18-C20, ICD-10) for 2004-2013 diagnoses. CRC data were linked with comorbidity data drawn from hospital records and health insurance claims. Logistic regression was used to model associations of comorbidity with age and stage.

RESULTS

For the 8462 CRC cases in this study, diabetes, peptic ulcer disease, and previous cancers were the most commonly recorded co-existing conditions. Most comorbidities were associated with older age, although some presented more frequently in younger people. Patients at both ends of the age spectrum (<50 and 80 + years) had an increased likelihood of CRC diagnosis at an advanced stage compared with other ages (50-79 years old). Adjusting for comorbidities moderated the association of older age with advanced stage. Conditions associated with advanced stage included dementia (OR = 1.25 (1.01-1.55)), severe liver disease (OR = 1.68 (1.04-2.70)), and a previous cancer (OR = 1.18 (1.08-1.28)).

CONCLUSION

Comorbidities are prevalent with CRC, especially in older people. These comorbidities differ in their associations with age at diagnosis and stage. Dementia and chronic heart failure were associated with older age whereas inflammatory bowel disease and alcohol access were associated with younger onset of the disease. Severe liver disease and dementia were associated with more advanced stage and rheumatic disease with less advanced stage. Comorbidities also interact with age at diagnosis and appear to vary the likelihood of advanced-stage disease. CRC patient have different association of age with stage depending on their comorbidity status.

Incorporation of functional status, frailty, comorbidities, and co-medication in prediction models for colorectal cancer survival

Limitations in functional status, frailty, multiple comorbidities, and co-medications are common among older colorectal cancer (CRC) patients. We investigated whether adding these factors could improve the predictive value of a reference model containing age, sex, tumor stage and location for prediction of 5-year overall survival (OS), disease-free survival (DFS), disease-specific survival (DSS), recurrence-free survival (RFS), and non-disease-specific survival (nDSS) for all CRC patients as well as for younger (<65 years) and older patients (≥65 years). Overall, 3,410 CRC patients from the DACHS study were analyzed and area under receiver operating characteristic curves (AUC) and net reclassification improvements (NRI) were assessed. In prediction of OS, the reference model plus functional status was identified as the best model among all CRC patients (AUC: 0.762) and younger CRC patients (AUC: 0.820). In older CRC patients, comorbidity should additionally be added (AUC: 0.747). For nDSS, the reference model plus comorbidity and frailty had the best predictive performance in all CRC patients (AUC: 0.776). For the outcomes DFS (AUC: 0. 727), DSS (AUC: 0. 838), and RFS (AUC: 0. 784), the reference model was already the best model in all CRC patients because no significant NRIs were observed. The pattern "The less CRC-specific the survival outcome and the older the CRC patients, the more relevant the inclusion of functional status, comorbidity, and frailty in CRC prognostic scores is" was observed. Thus, different nomograms for younger and older CRC patients for 1-, 3-, and 5-year OS prognosis estimation are being suggested.