This study aims to provide an overview of the health of people who use heroin and crack cocaine in England, and to assess the quality of healthcare for certain diseases.
People use illegal drugs in many different ways. In the UK, heroin and crack cocaine are strongly associated with drug dependence, social exclusion (such as homelessness and imprisonment) and acute and long-term health problems, which is why we are focusing on the health of people who use these particular drugs.
Many studies have shown that people who use heroin and crack cocaine have high risk of infections, mental health problems and drug overdose. A few studies also suggest that the risk of other diseases such as cancers, heart and lung diseases is also raised, but there is less evidence.
This project will use anonymised data from GPs. We will compare the way people who use heroin and crack cocaine use health services against the general population (i.e. people who are not known to use heroin or crack cocaine). Measures of health service use will include the number of GP appointments and A&E visits.
We will then flag patients who were diagnosed with certain diseases (including long-term breathing problems), and see if and when treatment was provided. This analysis is intended to identify specific issues with health service access. For example, if we find that patients with lung disease are not given flu vaccines, we could recommend promoting flu vaccines in drug treatment services.
There are an estimated 314,000 people who use heroin and/or crack cocaine in England. Although the risk of infections, mental health problems and overdose in this group is well-characterised, there is limited research into healthcare needs related to common non-communicable diseases. Some studies in the UK have reported the rate of hospital admission in this group related to chronic diseases, but these data do not provide insight into the frequency of diseases that do not require hospitalisation, or into healthcare quality.
We will use routinely collected data from CPRD, linked to hospital and mortality data. We will define and describe a cohort of people who use heroin and/or crack cocaine based on Read codes and prescription codes in CPRD, as well as diagnostic codes in hospital data. Although access to primary care among members of this group may be poor, existing evidence suggests that around 90% of people in this group are registered with a GP, and preliminary counts suggest 67,000 individuals can be identified.
We will describe the rate of cause-specific primary and secondary care utilisation, using ICD-10 chapters and subgroups, in our study cohort and a matched group from the general population. We will also apply unit costs to compare the costs of healthcare in each group, using life table modelling to account for differences in mortality.
We will then identify incident cases of certain diseases (including chronic obstructive pulmonary disease) and measure the probability of receiving secondary prevention interventions (such as pulmonary rehab) and adverse outcomes (all-cause mortality, mortality due to the incident disease, and unplanned hospital admissions due to the incident disease). This analysis is guided by patient and public involvement, and existing analyses of causes of excess death in this population.
Among all patients
1. Mortality
a. All-cause mortality
b. Cause-specific mortality (using ICD-10 chapters (such as cardiovascular diseases) and subgroups (which may be sections within chapters, such as ischaemic heart disease, or categories that cut across a number of chapters, such as bacterial and fungal infections, which include diagnoses in chapter I, infections, and chapter L, skin).
2. Healthcare utilisation
a. GP consultations (including practice nurse and health-care assistant)
b. A&E visits
c. Hospital admissions
d. Cause-specific hospital admissions and GP consultations (using ICD-10 chapters or existing disease phenotypes)
e. 30-day readmission rate among patients who are admitted
f. Outpatient visits
Among patients with specific incident diseases
3. Chronic obstructive pulmonary disease
a. Disease stage (using the COPD GOLD disease stages 1-4 [1])
b. Secondary prevention interventions (see appendices)
c. Adverse outcomes (all-cause mortality, death due to respiratory disease or unplanned hospital admission due to respiratory disease)
4. Cardiovascular disease
a. Whether blood pressure, BMI, and Q-risk values are recorded, and the recorded values.
b. Secondary prevention interventions (see appendices)
c. Adverse outcomes (all-cause mortality, death due to cardiovascular disease or unplanned hospital admission due to cardiovascular disease)
5. Bacterial and fungal infections: longitudinal patterns of health-care visits and mortality before and after hospitalisation.
Dan Lewer - Chief Investigator - University College London ( UCL )
Dan Lewer - Corresponding Applicant - University College London ( UCL )
Amitava Banerjee - Collaborator - University College London ( UCL )
Andrew Hayward - Collaborator - University College London ( UCL )
Arturo Gonzalez-Izquierdo - Collaborator - University College London ( UCL )
Caroline Shulman - Collaborator - University College London ( UCL )
Jennifer Quint - Collaborator - Imperial College London
Kenan Direk - Collaborator - University College London ( UCL )
Muhammad Qummer ul Arfeen - Collaborator - University College London ( UCL )
Naomi Van Hest - Collaborator - University College London ( UCL )
Neha Pathak - Collaborator - University College London ( UCL )
Paola Zaninotto - Collaborator - University College London ( UCL )
Robert Aldridge - Collaborator - University College London ( UCL )
Spiros Denaxas - Collaborator - University College London ( UCL )
Thomas Brothers - Collaborator - University College London ( UCL )
HES Accident and Emergency;HES Admitted Patient Care;HES Outpatient;ONS Death Registration Data;Patient Level Index of Multiple Deprivation