For the NHS, winter is the most cruel season. Winter is the season of flu epidemics and the time of year when hospital casualty departments resemble war zones.
For this reason the NHS can depend on announcements of extra dollops of cash each autumn to hire extra staff and open extra beds. There is an official recognition of the special problems that winter brings: hospitals need extra money in order to cope with the additional volumes of emergency admissions which appear each winter.
The cruelty of NHS winters does not stop there. There is a well-accepted convention that winter upsurges in emergency admissions also cause problems for hospitals' elective workload.
Health secretary Frank Dobson has trumpeted the significant summer and autumn drops in the numbers of people on hospital waiting lists because he fears what a bad winter might do to these highly politicised statistics.
Indeed, when the November waiting list figures were announced, the Department of Health cautioned that future statistics would show a 'distinct slowdown' as winter pressures began to bite.
But how well-grounded is this fear that a winter surge in emergency admissions will jeopardise waiting list targets?
Is there hard statistical evidence to back the assertions that January's emergency inpatients are admitted to hospital only at the expense of elective cases? Anecdotally, it is not difficult to find evidence to explain the anxiety.
Information managers the length and breadth of the NHS are only too familiar with the post-Christmas task of trying to quantify the damage done to hospital waiting lists by a particularly bad cold snap. Purchasers are often forced to relax their insistence on 12-month waiting-time guarantees if hospitals can prove that elective beds have had to be commandeered for emergency admissions.
If anecdote is not enough, there is plenty of 'official' evidence to go on. Taking a recent example, the association between increased emergency admissions and longer waiting lists was confirmed in December in Scotland by an Accounts Commission report. One of the first observations in the executive summary of this document was that 'increasing numbers of emergency admissions. . . put pressure on hospitals, leading to waits in A&E, cancelled operations and longer waiting lists'.
1But is the relationship between increased emergency admissions in winter and longer waiting lists really as axiomatic as this? It is worth exploring in more detail, because if winter pressures do lengthen waiting lists, we would expect hospital statistics to tell us three things:
that waiting lists are longer at the end of autumn and winter quarters than at the end of spring and summer quarters;
that there are more emergency admissions in autumn and winter than in spring and summer;
that there are fewer elective admissions in autumn and winter than in spring and summer.
Looking at Scottish hospital statistics over the past five years, do the figures confirm these expectations? It is important to acknowledge that in many ways we are watching a moving target. All three of these indicators - waiting lists, emergency admissions and elective admissions - have shown significant movement over the past five years. Scottish hospital waiting lists, for example, fell from 79,000 in June 1993 to 75,000 two years later, before climbing to their June 1998 level of 84,000. Hospital admissions have been on the move, too, with both elective and emergency admissions increasing by about 15 per cent over the five-year period.
But, by concentrating on the quarterly averages, and by comparing winter and summer quarters, these trends can largely be glossed over. It is still possible to obtain an accurate picture of the seasonal variation regardless of long-term changes over time.
So do the statistics supply evidence to suggest that waiting lists get longer in winter? Commonsense, anecdote and everyday experience all suggest this should certainly be the case. And, of course, the statistics confirm this conjecture. As figure 1 shows, a typical NHS year begins with hospital waiting lists at their longest on new year's day. Each successive quarter then reduces the list until the autumn months when they begin to soar again.
Also, as figure 2 demonstrates, there appears to be a clear pattern to emergency admissions: they are higher in winter than in summer. At their highest in the October December quarter, emergency admissions then reduce as the year progresses. The typical pattern in Scotland over the past five years has been for there to be 4,000 fewer emergency admissions in the quarter ending September than in the quarter ending December. So it is easy to see why the link has been made between winter emergency admissions and higher waiting lists.
But waiting lists are complex beasts, notoriously reluctant to respond to attempts to shorten them. Does it really make sense to try to explain variations in waiting list size by reference to changes in emergency workload?
Although it can surely be no coincidence that waiting lists lengthen in winter, it has to be conceded that they are more likely to be affected by the pattern of elective admissions than emergency admissions. If the process were to be as simple as we think - that emergency admissions displace elective admissions in winter - then we would expect the figures to show a winter dip in elective admissions, too.
Patterns in elective and emergency admissions
But the statistics for seasonal variation in elective workload, shown in figure 3, blur the picture. With the exception of the autumn quarter, elective admissions follow a surprisingly similar pattern to emergency admissions. Indeed, the most striking features of this figure are that, first, it is the winter quarters where elective admissions are at their peak, and, second, summer quarters where elective activity is at its lowest.
Could it be that the real seasonal problem for the NHS is not the high level of emergency admissions in winter but, rather, the low level of elective activity in summer? Low levels of activity, moreover, which are occurring at precisely the times of year when they are least likely to be jeopardised by emergency overflow.
It is tempting to conclude that the winter waiting list difficulties are not quite as connected with the ravages of flu epidemics and cold snaps as we have been led to believe. Instead it appears more likely that seasonal variation in waiting list numbers is caused by the slowdown in activity in summer months. Shakespeare famously wrote that 'summer's lease hath all too short a date'. As far as the NHS's waiting list admissions are concerned, this is all too precise an observation: it's not shorter winters the NHS needs, but longer summers.
1 Accounts Commission for Scotland, 1998. Managing hospital admissions and discharges, Edinburgh .
The relationship between increased emergency admissions and longer waiting lists in winter has not been proven.
Waiting lists are more likely to be affected by patterns of elective work than emergency admissions.
Slowdown in elective work in summer is at the root of winter problems.