Key Health Data for the West Midlands 2000: Chapter 5

The purpose of this chapter is to give an overview of the numbers of hip replacements in the West Midlands. Primary total hip replacements and revisional procedures were grouped into the new PCT boundaries.

5.1.2 Data Sources

The data was obtained from the hospital episodes statistics (HES) database. Only elective procedures with operation codes (OPCS 4) W371, W381 and W391 for primaries and W373, W383 and W393 were analysed due to low numbers for the other categories.

	Table 5.1. Key to OPCS codes

Average Length of Stay

Average length of stay was calculated by dividing the total number of bed days by the number of primary procedures carried out by PCT (see Figure 5.2). The calculation was repeated for revisional procedures (see Figure 5.4). Average Length of stay ranged from 9.6 days in South Worcestershire to 13.5 days in South Western Staffordshire. Figure 5.1 shows a map for the average length of stay for primary hip replacements carried out in 1999 -2000.

Standardised Rates

Direct standardised rates were calculated for primary and revisional procedures for 1999 - 2000 data. Standardisation is used to remove as far as possible the differences in the effects of age and other confounding variables when comparing two or more populations. The analysis applies the observed admission rates in the study population to a standard population. (See Table 5.3 and 5.4)

Surgical Volume

Data on the number of consultants carrying out hip replacements in each trust was obtained. This data allowed us to calculate the surgical volume (see Table 5.6)

	Table 5.2. Average length of stay for primary hip replacement operations 1999 - 2000

	Figure 5.1. Map of average length of stay for primary hip replacements, 1999 - 2000

	Table 5.3. Age / sex standardised rates for primary hip replacements 1999 - 2000

	Figure 5.2. Map of age / sex standardised rates for primary hip replacements 1999 - 2000

	Table 5.4. Average length of stay for revisional procedures, 1999 - 2000

	Table 5.5. Age /sex standardised rates for revisional procedures 1999 - 2000

	Table 5.6. Surgical Volume, 1999 - 2000.

Coronary Heart Disease

5.2.1 Introduction

Coronary Heart Disease (CHD) is the most common cause of death in the UK. In the West Midlands, whilst deaths from CHD have seen a modest reduction year-on-year over the last five years (Fig 3.1), death rates are still higher than that for England as a whole.

	Figure 5.3. Deaths from CHD in the West Midlands 1996-2000 inclusive, rates per 10,000

CHD was the subject of the first of the Government's National Service Frameworks (NSF) (Department of Health, 2000).
The NSF lays down key National performance targets relating to the prevention and treatment of CHD. A key theme of the framework is equality of service response. It has been clearly shown that there is a strong socio-economic gradient in CHD prevalence. In a region such as the West Midlands, The population is highly heterogeneous in terms of socio economic status, age, morbidity and ethnicity. Consequently, service commissioners are faced by widely differing demands for treatment.

The aim of this chapter is to briefly summarise the differing rates of CHD mortality and morbidity found in PCT populations across the region and to contrast these with the distribution of surgical revascularisations.

5.2.2 Data sources

Hospital admissions were obtained from Hospital Episode Statistics for financial year 1999-2000, the most recent available data. Secondly, mortality statistics were obtained from the Office for National Statistics for the calendar year 2000. In both cases individuals were allocated to PCT resident populations by postcode matching. Standardisations were based on populations projected from the 1991 census.

CHD prevalence is difficult to measure. Many cases present in primary care settings. The difficulty here is that information systems are not sufficiently developed to compare these presentations accurately between localities. Hospital presentations are easier to measure as we can use the hospital national minimum data set. These acute presentations can be used as an approximate comparator for the levels of disease that probably exist. In this case we used the standardised rates of CHD-related emergency admissions per 10,000 population (Figure. 3.2). Mortality is similarly seen as an indicator of underlying morbidity and is summarised in Fig. 3.3, where the standardised mortality rate per 10,000 of population was used.

A common CHD treatment is surgical revascularisation, either by coronary artery by-pass grafting (CABG) or percutaneous transluminal coronary arthroplasty (PTCA). Whilst only a minority of sufferers require surgery, owing to the total numbers involved, the operations are common in absolute terms. Over 4000 were performed in the West Midlands in 1999-2000 (source PTCAs and CABGs (source: Hospital Episode Statistics for financial year 1999-2000). This amounts to significant proportion of cardiac surgical activity in the region. Also it is an intervention of proven effectiveness, a fact reflected in the CHD NSF which commits the service to increasing the numbers performed to 750 procedures per million for each of the two types of operation.

Figure.3.4 shows the distribution of revascularisations (using standardised rates per 10,000) in PCT populations across the West Midlands. Once again a variation is noted, however when compared to the two maps showing mortality and morbidity it can be seen that the areas with the highest supply of surgery do not necessarily have comparatively high levels of discernable disease.

References

Department of Health, 2000, National Service Framework for Coronary Heart Disease, http://www.doh.gov.uk/nsf/coronary.htm.

	Table 5.7. Age / sex standardised rates of Emergency CHD-related admission, mortality and revascularisation, by PCT boundary 1999 / 2000

	Figure 5.4. Emergency CHD-related admission rate by PCT resident population 1999-2000

	Figure 5.5. Death rate by PCT resident population 1999-2000

	Figure 5.6. Revascularisation by PCT resident population 1999-2000