Measuring Levels of Comorbidity in Drug User* Emergency Patients Treated in Ontario Hospitals

Abstract

We examined the nature and extent of health problems in drug user patients initially treated in emergency departments and who were subsequently admitted to all hospitals in Ontario, using data from the Hospital Medical Records Institute (HMRI). The modified standardized morbidity ratio (modified SMR) is introduced to improve the measurement and visual display of reduced morbidity as well as excess morbidity. During 1985–86, about 75% of drug user patients entered hospital through the emergency department. There were 5077 emergency patients with primary drug use-related diagnoses and 9827 with secondary drug use-related diagnoses. Cases with poisoning diagnosis made up over 80% of all drug use cases treated in emergency departments. Cases with non-dependent abuse of drugs accounted for 8–12% of emergency drug user patients, whereas those with drug dependence accounted for about 3% of emergency drug user patients. These patients had more than three times the comorbidity experience of all hospital patients. They had excess comorbidity due to mental disorders, infectious and parasitic disorders, and injury and poisoning diagnoses. However, they had reduced comorbidity due to complications of pregnancy, childbirth, and the puerperium and from congenital anomalies and conditions originating in the perinatal period. Cocaine patients were more likely to have infectious parasitic diseases and diseases of the skin and subcutaneous tissue, while amphetamine patients were more likely to have diseases of the digestive system and of the musculo-skeletal system and connective tissue.

Keywords:

• drugs
• co-morbidity
• treatment
• measurement
• statistical techniques

Notes

Notes

*The journal's style utilizes the category substance abuse as a diagnostic category. Substances are used or misused; living organisms are and can be abused. Editor's note.

1. Drug users represent a heterogeneous group of people who use a variety of drugs in various ways and combinations for a range of times and represent a range of appropriate and inappropriate types and levels of functioning. This heterogeneity is a factor that can have an effect on the types and levels of drug user health and illness, the types and ranges of services and treatment seeking, and the use of available and accessible resources.

2. Murray and Lopez (1996) indicate that, in 1990 in the developed world (“developed regions”), drug use is the 6th leading cause of disability adjusted life years (DALYs) in males aged 14 to 44.

3. The inverse of a number is 1 divided by that number. For example, the inverse of 10 is 1 divided by 10, which is equal to 0.1.

4. For instance, pregnancy in a patient whose sex is indicated as “male” would be an error automatically picked up by the computer, and HMRI would flag this error to the reporting hospital in order for it to be corrected.

5. Within the ICD-9 classification system, in addition to the usual diagnoses, there is an additional secondary classification system available for medical conditions due to external causes such as accidental or intentional injuries and poisonings. For example a person who is treated for “poisoning by opiates and related narcotics” (ICD code 965.0) may also have a secondary diagnosis of “accidental poisoning by opiates and related narcotics” (ICD code E850). E-codes can only be used for secondary diagnoses.

6. We excluded cases with alcohol diagnoses in this study.

7. Numerous other psychoactive substances that can be used or misused are recognized by ICD-9 but only a few have unique diagnostic code numbers that are ascribed to one substance only.