Transcript presentation - Society for the Study of Addiction

General Practice is an efficient place to manage
the complexities of drug addictions
Dr David Carson, Dr Roy Robertson
Muirhouse Medical Group, 1 Muirhouse Ave, Edinburgh EH4 4PL
Aims of Case Study
This poster provides an insight into our current drug-dependent patient population,
their management and the associated blood borne virus (BBV) problems. It
demonstrates how this has evolved over the years and shows what structures we
have in place in general practice to diagnose, treat and support patients with
complicated, multi-dimensional problems.
Background
Muirhouse Medical Group is a large NHS general practice in a deprived area of
Edinburgh that has, since the 1980s, had a significant caseload of young patients
with addiction problems. Over the past three decades, many different approaches
have attempted to address these issues, with varying success. The current mainstay
of treatment is the prescription of opiate substitution therapy (OST), largely in the
form of methadone or dihydrocodeine, but also buprenorphine (Suboxone). We
currently have around 11,500 patients, of whom around 400 are receiving OST. The
co-morbidities of hepatitis and HIV disease have been well monitored and
documented over the years. As the population is ageing, and a recent influx of
various immigrant populations has been seen, the character and management of
the drug dependent patient population and those with BBVs is evolving.
In 1985 there 192 drug dependent patients registered with us. This peaked around
2001-2003 at over 700 patients and has nearly halved to give today's figures of
around 400. As the overall practice population has continued to increase, this
therefore reflects a real reduction is the proportion of drug dependent patients in
our area (Figure 1).
Proportion of Registered Drug Dependent Patients as
Percentage of Total Practice Population
% of Practice Population
6
5.5
5
4.5
4
3.5
3
1993 1994 1995 1996 1997
2006 2007 2008 2009 2010 2011 2012 2013
Year
Figure 1. The Proportion of drug dependent patients expressed as
percentage of total practice population over the past 20 years.
METHADONE DIHYDROCODEINE BUPRENORPHINE
NUMBER OF
PATIENTS
260
103
12
DOSE (mg)
Min-Max (AVE)
5-250 (90)
180-1800 (700)
0.6-16 (7.3)
AGE (YEARS)
Min-Max (AVE)
20-64 (38.3)
27-68 (44.7)
29-51 (39.5)
MALE / FEMALE
(%)
65% / 35%
60% / 40%
83% / 17%
Figure 2. Current Opiate Substitution Therapy (OST) prescribing at MMG.
Evolving Blood Borne Virus Problem
HIV Disease
From the early 1980s, the rate of HIV infection was very high in the intravenous
drug using population, with 98 HIV+ patients registered in 1989 almost exclusively
within a population of little more than 200 IV drug users {1}. By 2007, this figure
had fallen to only 47 patients, of whom just over half (25) were current or had a
history of IV drug use and 10 were from overseas. By 2013, the total number of
patients with HIV has remained similar (46) however the population had changed
significantly. Amongst the 46 HIV patients, now only 13 had a history of IV drug
misuse and 21 HIV patients were from overseas (largely sub Saharan Africa).
Our IVDU population is ageing. The average age in 2007 was 40.6 years but had
risen to 43.4 by 2013. It is a largely transient population with 19 patients (41%)
leaving our practice. Four patients died from HIV related illnesses. All were on OST,
were in their forties and had been diagnosed between 1985-1995. The proportion
of HIV infected men who have sex with men has remained similar at about 10% of
the infected population.
Hepatitis C
In recent years, Hepatitis C has become the most prominent BBV with transmission
via IVDU. Presently, we have 80 patients actively infected, of whom 72 patients
(90%) have a history of drug misuse. Currently 52 (72%) of the Hepatitis C positive
drug-abusing population are prescribed opiate substitution therapy (39
methadone, 11 DHC, 2 buprenorphine). 25 patients have been successfully treated
(16 drug dependent) at our local clinic and hospital ID departments with another 44
patients spontaneously clearing infection (31 drug dependent).
Hepatitis B
With a large volume of overseas immigrants, Hepatitis B has also has an increasing
prevalence. We currently have 35 carriers (aged 13-54) although only 2 have a
history of IV drug use. The majority (28, 80%) are from overseas, with 15 (43%)
coming from China alone. 2 patients have concurrent Hep C (both IVDUs) and one
has HIV (MSM).
Current Drug Using Population
In December 2012, a review of our OST prescribing was performed. In total, we
had 375 patients on OST, with around another 10% of drug-dependent patients
on non-opiate prescriptions (mainly benzodiazepines). The breakdown of the
different OST use, the dosage, as well as the age and the gender the patient
populations are shown in Figure 2.
As the majority of opiate dependent patients are stable, they are seen at 8
weekly intervals in routine GP surgeries where their prescriptions are issued for
the following 8 weeks. Patients collect their medication from local pharmacies at
variable frequencies, from daily supervised consumption to unsupervised weekly
dispensing, depending on how stable and reliable they are. The GP appointments
offer the clinician opportunities to holistically assess the patient, including
discussion of a recovery plan, any illicit drug or alcohol use, titration of OST dose,
a chance to perform urine toxicology, an assessment of mental health and risk
factors for BBV. Opportunistic BBV blood testing can also be performed. This
creates an annual demand for 2,500 appointments, equating to approximately 50
drug dependent-related consultations each week. Due to the chaotic lifestyle of
many of these patients, a significant proportion present late on the day that their
prescription is due to be renewed. The practice employs a rigid appointment
system but allows drug dependent patients to be added on to the end of each
GP’s surgery as ‘emergencies’ at very short notice. Not only does this ensure that
no doses of OST are missed but also reduces the rate of non-attendance of prebooked appointments.
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Support from specialist Services and Secondary Care
We enjoy a close relationship with our community drug problems service. They
hold weekly clinics within our building which we can book directly, with only four
days notice, through our common appointment system.
There is also an outreach centre based within addiction and psychiatric services,
located only 5 minutes walk from the surgery. We have two central hospital
referral services. The regional Infectious Disease unit is 15 minutes walk away, with
an alternative hepatitis referral pathway at Centre for Liver and Digestive Disorders
located across the city.
Conclusions & the Future
We are managing an ageing population of reducing in size with long term
addiction problems. We have demonstrated that our OST prescribing has reduced
death rates from overdose and BBV infection. Our incidence of HIV has reduced &
is currently stable. Hepatitis C is currently the area where we have focussed
resources and are seeing an improvement as a result. We have a planned Hepatitis
C clinic weekly within the surgery building, with hospital based nurse specialist
supported by GP and healthcare assistant to further improve our care. The
increase in immigration presents new challenges with Hepatitis B.
References
1. JR Robertson, PJM Ronald, GM Raab, AJ Ross, T Parpia. Deaths, HIV infection, abstinences &
other outcoomes in a cohort of injecting drug users floowed up for 10 years. BMJ 1994; 309:
369-72