Increasing patient choice in the management of minor ailments in primary care

41 Pages·2002·0.21 MB·English

CENTRE FOR HEALTH ECONOMICS
Increasing patient choice in the management of
minor ailments in primary care
Chris Bojke
Hugh Gravelle
Karen Hassell
Zoe Whittington
CHE Technical Paper Series 23

CENTRE FOR HEALTH ECONOMICS TECHNICAL PAPER SERIES
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Health Economics, University of York.
February 2002
© Chris Bojke, Hugh Gravelle, Karen Hassell, Zoe Whittington
2
Increasing patient choice in the management of minor
ailments in primary care*
Chris Bojke+ Hugh Gravelle+ Karen Hassell++
Zoe Whittington++
Abstract. We examine the effects of a feasibility scheme to provide easier access to
pharmacists for patients with minor ailments. The scheme allowed pharmacists to prescribe
and dispense medicines currently limited to general practitioners (GPs) without patients
loosing their right to free prescriptions. We formulate a model of the rationing of GP
consultations and GP supply decisions. We estimate a reduced form equation for total GP
consultations and find that they are unaffected by the intervention but that the proportion for
minor ailments decreases. We also examine patient choices between GP and pharmacies
with a variety of multinomial models and find that the main determinant is the type of minor
ailment. Distance appears to have no effect on patient choice.
JEL Nos: I11, I18
Key words: Access. Primary care. Pharmacy. Consultations.

+ National Primary Care Research and Development Centre, Centre for Health Economics,
University of York, York, YO10 5DD
++ School of Pharmacy and Pharmaceutical Sciences, University of Manchester, Manchester
M13 9PS
3
1. Introduction
In the British National Health Service patients register with a general practitioner (GP) and
about 90% of patient contacts with the NHS take place in primary care. Most consultations
are for minor ailments [1,2] and typically result in the GP writing a prescription for the
patient to take to a commercial community pharmacy for dispensing. Many GPs perceive
consultations for minor ailments as an “inappropriate” use of their time. There is evidence
that many GP consultations for minor ailments can be dealt with satisfactorily by community
pharmacists providing advice and dispensing an over the counter (OTC) product which
does not require a doctor’s prescription [3]. Government policy is to encourage the shifting
of demand for minor ailment consultations from GPs to pharmacists [4].
One way to shift demand is to extend the range of medicines which pharmacists can provide
to patients without a doctors prescription. Figure 1 illustrates schematically the effect of such
a change on different groups of patients. Patients with minor ailments are distributed along a
road on which are situated a pharmacy and a GP surgery. Travel costs imply that patients at
different points on the road have different net benefits from consulting the pharmacy and the
GP. Patients further away from the surgery or the pharmacy have lower net benefits, as
shown by the height of the relevant net benefit lines. All patients to the left of the pharmacy
prefer a pharmacy consultation to a GP consultation, though those who are far enough from
the pharmacy will consult neither the pharmacy nor the GP. Similarly for patients to the right
of the GP. Patients between the pharmacy and the GP may go to either depending on the
height of the net benefit curves.
Initially, with the net benefit curves for the pharmacy and GP at bphand bgppatients
1 1
between p and d go the pharmacy and those between d and g go to the GP. An increase
1 1 1 1
in the range of medicines which the pharmacy can prescribe shifts the net benefit curve from
consulting the pharmacist to bph. Initially patients between d and d¢ are attracted from the
2 1 2
GP to the pharmacy. If there is no change in the supply of consultations by the GP, the
reduced demand at the GP will lead to a reduction in waiting times for appointments. The
net benefit curve for GP consultations shifts upward to bgp. When the pharmacist is able
2
4
prescribe a wider range of medicines, minor ailment patients between p and d go the
2 2
pharmacy and those between d and g go to the GP.
2 2
Patients between p and p who did not previously consult either the GP or the pharmacist
2 1
now consult the pharmacist and are better off. Those between p to d who previously
1 1
chose the pharmacist gain because they get greater benefit from consulting. Patients
between d and d who shift to the pharmacy from the GP also gain because they shift to a
1 2
preferred option. Patients between d and g who continue to consult the GP gain from
2 1
reduced waiting times at the surgery and the patients between g and g who now consult the
1 2
GP also gain.
There will also be gains to patients who consult the GP for non minor ailments because of
the reduction in waiting times for appointments. The gain will accrue both to the infra
marginal patients who previously consulted the GP and to those who are now induced to
consult or to consult more frequently.
The change in the rules to widen the range of products which pharmacists can prescribe will
also change NHS costs. There may be an increase in NHS prescriptions for minor ailments
because more minor ailment patients are seen in total. GP costs may change if the GPs
change their supply of surgery sessions in response to the change in the mix of their patients.
Finally, there may be changes in NHS costs because of the increase in non minor ailment GP
consultations.
There has been no overall cost benefit analysis of policies to encourage use of pharmacists
as a substitute for GPs and there is little evidence about the magnitude of possible demand
shifts. Philips et al [5] examined the effect of a scheme to encourage patients to use
pharmacies for advice and prescription for head lice. The proportion of head lice patients at
pharmacists who were referred by their GP fell from nearly 80% to just over 10% over the
course of the intervention. There were also significant cost savings, mainly because of a
lower cost of pharmacists’ time compared with GP time and because the pharmacists were
restricted to a smaller range of products for head lice than the GP.
5
Our study is complementary to Philips et al [5]. We examine an intervention which covered
a wider range of minor ailment conditions. We focus on the demand implications and do not
consider the cost implications of easier access. We look at the effect of the intervention on
GP workload, and on the numbers of minor ailment and non minor ailment consultations.
We also examine the factors which affected patients’ choices between GP and pharmacist
consultations for minor ailments.1
We first set out a simple model of the rationing of GP consultations. We use the model to
guide the empirical analysis of the responses of patient demand and GP supply of
consultations to the change in the accessibility of pharmacies.
2. Modelling the implications of easier access
2.1 GP workload
There are no charges for GP consultations. Demand depends on the waiting time for a
consultation, other costs incurred by patients and the costs and convenience of the
alternative of seeking advice direct from a pharmacy. As with the market for elective
admissions to hospitals, the market for consultations is cleared by adjustments in waiting
times. We first set out a simple model in which patients consult a GP by booking an
appointment in advance. We then discuss the equilibrium in the market when patients can
also consult a GP by turning up at the surgery and waiting to be seen and suggest that the
implications of the model with booked appointments for the interpretation of our data are
unaffected
Divide GP consultations into those for minor ailments and those for all other reasons. Denote
expected demand for minor ailments by D (t,k,y), D < 0,D <0, and for other
1 1t 1k
consultations by D (t,y), D < 0 where t is the waiting time for an appointment. k is
2 2t
parameter reflecting the convenience or net cost of a pharmacy consultation and y is a
~
vector of demand shifters. Realised demand for each type of consultation is D = D +e
i i i

1 A full account of the study is contained in Whittington et al [6] and a summary in Hassell et
al [7].
6
(Ee = 0), which may differ from expected demand, as the literature on missed appointments
i
suggests [7].
The practice’s GPs plan to supply S consultations in a session. Decisions on planned supply
(the number of GPs taking consultations in the session) are made before realised demand is
known. Increases in planned supply S reduce the length of time patients have to wait for an
appointment. There is equilibrium when planned supply equals planned demand:
D (t,y,k)+ D (t,y)- S = 0
1 2
and the equilibrium waiting time is
t = t(S,y,k), t < 0, t < 0.
S k
The GPs always see the actual number of patients who turn up at a session. Their actual
~
supply S is equal to the realised demand for that session:
~
S = D (t,y,k)+e + D (t,y)+e
1 1 2 2
and because planned supply equals expected demand in equilibrium
~
S = S +e +e
1 2
In Figure 2, the demand curves plot expected demand for GP consultations against the
waiting time for an appointment. Suppose initially that the planned supply of GP
consultations is fixed and consider the effect of easier access to pharmacies, modelled as an
increase in k. (In terms of Figure 1, the net benefit curves for pharmacy consultations shift
upward.) Total expected demand for GP consultations at any waiting time is reduced and
waiting time falls to clear the market. Since the demand curve for GP consultations for other
conditions is unchanged, there are more expected consultations for them. The expected
number of minor ailment GP consultations is reduced by easier access to pharmacies and
increased by the reduction in waiting time. Since the overall supply of consultations is fixed
and the expected number of other consultations has increased, the overall effect of easier
access to pharmacies is to reduce the expected number of minor ailment GP consultations:
D + D t < 0. In Figure 2 the aggregate expected demand curve shifts down and waiting
2k 2t k
time falls, leading to an increase in other GP consultations and a reduction in minor ailment
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GP consultations. The smaller the elasticity of other consultations the less the fall in the ratio
of expected minor ailment consultations to expected total consultations. Only if demand for
other consultations is perfectly inelastic will the expected number and proportion of minor
ailment consultations be unchanged: the expected minor ailment consultations diverted to
pharmacy are replaced by additional minor ailment consultations generated by the fall in
waiting time.
The planned supply of consultations offered by GPs may depend on the expected mix of
consultations. They might regard consultations for non minor conditions as more deserving of
their time and so increase their time input as the proportion of minor ailment consultations
decreases. Suppose that the practice GPs choose planned supply to maximise expected
utility
Eu = a E[D (t,y,k)+e ]+a E[D (t,y)+e ]- EC(S +e +e ,z)
1 1 1 2 2 2 1 2
where a is the weight on the i’th consultation. GPs who dislike “inappropriate” minor
i
ailment consultation have a < a > 0 and possibly a < 0. C is the cost of consultations
1 2 , 1
and z is a cost shifter. Assume that the cost function is linear in the total number of
consultations, with marginal cost c(z), so that EC = c(z)E(S +e +e ) = c(z)S . Using t
1 2
= t(S,y,k), the first order condition
[ ]
dEu/dS = a D +a D t - c(z)= 0
1 1t 2 2t S
yields the planned supply of consultations S*(k,y,z).
~
We estimate the reduced form workload equation S = S*(k,y,z)+e to test the effect of
easier pharmacy access on GP workload. Predictions about the effects of demand and
supply shifters on realised workload are based on their effects on planned supply S*.
Increases in the marginal cost of GP consultations reduce GP planned supply (and raise
waiting times and reduce expected demand by an equal amount). The response of planned
GP supply to demand shifts is less obvious. Thus for easier patient access
¶ (cid:230) dEu(cid:246) [( ) ( ) ]
sgn S* =sgn (cid:231) (cid:247) =sgn a D +a D t t + a D +a D t +a D t
k ¶ kŁ dS ł 1 1tt 2 2tt k S 1 1t 2 2t Sk 1 1tk S
8
where
1 [ ( ) ( )]
t = D D + D - D D + D
( )
Sk D + D 3 1k 1tt 2tt 1tk 1t 2t
1t 2t
The effect of easier pharmacy access on planned supply of consultations S*(k,y,z) is
ambiguous, even with this simple specification, without quite detailed further restrictions on
the form of the expected demand functions. For example, if demand is linear in waiting time
and pharmacy access, then planned GP supply and hence expected GP workload is
unaffected by the change in pharmacy access.
The effects of demand and cost shifters on the mix of minor ailment and other GP
consultations is also ambiguous. We observe ~r = D~ /D~. The effect of the cost shifter z
1
which raises the marginal cost of supply and thus reduces planned supply has
Ø ø Ø ø
D t D t D D
sgn ~r = sgnŒ ~1t - ~2t œ =sgnŒ w ~1 - w ~2œ
z 1t 2t
º D D ß º D D ß
1 2 1 2
where w is the elasticity of demand for the i’th type of consultation with respect to
it
expected waiting times. The expected effect on the mix is more likely to be negative the
more elastic is the expected demand for minor ailment consultations. The effect of easier
access is more complicated but if expected demands are linear in waiting time and pharmacy
access, so that planned supply of GP consultations does not change, the realised proportion
of consultations for minor ailments will fall.
The above account neglects the fact that patients can choose between booking an
appointment or attending a GP surgery session without an appointment and waiting in the
surgery until they can be seen. The complication does not affect the basic structure of the
model. Queuing theory suggests that there will be a distribution of waiting times at the
surgery for those attending without an appointment because of random fluctuations in the
rate at which GPs see unbooked patients and in the rate of arrival of unbooked patients. An
increase in planned supply will reduce expected surgery waiting times and an increase in
demand will increase them. If demand for unbooked consultations falls as expected in
surgery waits increase, the markets for booked and unbooked consultations will be cleared
9