4. NHS Board areas: trends, causes, drugs reported, and death rates by age group and relative to the estimated number of problem drug users

4.1 Deaths are normally classified by geographical area on the basis of the usual place of residence of the deceased (or, if that is not known, or is outwith Scotland, on the basis of the location of the place of death). In this publication, the statistics for each NHS Board's area are based on the boundaries which apply with effect from 1st April 2014. The figures for earlier years have been revised (where appropriate) to show what the numbers would have been, had the new boundaries applied in those years (the main changes are for Greater Glasgow & Clyde and Lanarkshire; there are also occasional minor revisions for Fife and Lothian). Table HB1 shows the numbers of drug-related deaths for each NHS Board area. Of the 526 deaths in 2013, 138 (26 per cent) were in what is now the Greater Glasgow & Clyde NHS Board area. Lothian, with 90 (17 per cent), had the next highest total followed by Lanarkshire (75 or 14 per cent), Grampian (50 or 10 per cent), Fife (39 or 7 per cent), Tayside (36 or 7 per cent) and Ayrshire & Arran (also 36 or 7 per cent).

4.2 Because of the generally small numbers involved, particularly for some NHS Board areas, great care should be taken when assessing any apparent trends shown in the table. Year-to-year variation in the figures could result in apparently large percentage changes. This is more likely for the areas with smaller populations, but can also be seen sometimes in the figures for the more populous areas (e.g. for what is now the Greater Glasgow & Clyde area: 147 in 2004; 109 in 2005; 156 in 2006). Therefore, using 5-year moving annual averages should 'smooth out' the effects of any fluctuations, and so provide a better indication of the longer-term trends. The areas with the largest increases between their annual averages for 1999-2003 and 2009-2013 were what is now Greater Glasgow & Clyde (up by 44, from 128 to 172), Lothian (up by 39, from 42 to 81), what is now Lanarkshire (up by 32, from 32 to 64), Tayside (up by 27, from 16 to 43), Fife (up by 25, from 11 to 36), Ayrshire & Arran (up by 15, from 24 to 39) and Forth Valley (up by 12, from 11 to 23).

4.3 The table also shows the population of each NHS Board area, and what its average number of drug-related deaths per year (for 2009-2013) represented per 1,000 population (using the population in the middle of the 5-year period as a proxy for the average population over the whole period). For Scotland as a whole, the average of 544 drug-related deaths per year represented a rate of 0.10 per 1,000 population. The area with the highest rate was Greater Glasgow & Clyde (0.15); next highest were Ayrshire & Arran, Fife, Lanarkshire, Lothian and Tayside, all of which had rates of 0.10.

4.4 Table HB2 gives a breakdown by cause of death for each NHS Board area for 2013. Table HB3 shows some geographical differences in the reporting of certain drugs: figures which should be used with particular care, in the light of the points mentioned in sections 2 and 3.3, the effects of which could be proportionately greater on the figures of some of the areas with lower populations. Note also that the figures given in Table HB3 are on the standard basis (drugs implicated in, or which potentially contributed to, the cause of death), and so are not comparable to figures (in the editions for 2008 and earlier years) on the basis of ‘all drugs which were [reported as having been] found to be present in the body’. As mentioned earlier, this website has versions of Table HB3 which give (i) figures for 2008 on the standard basis and (ii) figures for 2009 onwards on the ‘all drugs which were found to be present in the body’ basis.

4.5 Table HB3 shows the drugs reported for NHS Board areas. Overall, heroin/morphine was believed to have been implicated in, or to have potentially contributed to, 42 per cent of the total number of drug-related deaths in 2013 - but for noticeably above-average proportions in Fife (25 out of 39) and Tayside (20 out of 36) and for particularly low proportions in Grampian (16 out of 50) and Lothian (28 out of 90). Methadone was implicated in, or potentially contributed to, 41 per cent of drug-related deaths overall; with unusually high proportions in Ayrshire & Arran (23 out of 36) and Grampian (26 out of 50) and rather low proportions in Highland (4 out of 18) and Lanarkshire (19 out of 75). The table also shows that benzodiazepines were implicated in, or potentially contributed to, high proportions of drug-related deaths in Fife (17 out of 39), Grampian (36 out of 50) and Tayside (16 out of 36), and low proportions in Greater Glasgow & Clyde (15 out of 138) and Lanarkshire (8 out of 75), compared to 28 per cent for Scotland as a whole - although this comparison might be affected by the differences in reporting practices which are mentioned in sections 2.

4.6 Table HB4 provides, for each NHS Board area, for a number of age-groups, the drug-related death rate per 1,000 population. As with the overall rates in Table HB1, the figures were calculated using the average number of drug-related deaths per year (for 2009-2013), by taking the population in the middle of the 5-year period as a proxy for the average population over the whole period. Even though the figures are five-year averages, they must still be used with caution for the less populated areas (e.g. when the annual averages for 2007 to 2011 were calculated, just three 15-24 year old drug-related deaths in Shetland caused it to have a rate for that age-group which was double that of Scotland as a whole). Of the more populous areas, Greater Glasgow & Clyde had the highest drug-related death rates: 0.42 for 35-44 year olds and 0.21 for the 45-54 age-group; both well above the overall average rates for Scotland as a whole for the same 5-year period (0.26 and 0.12, respectively). Fife and Tayside had rates for 25-34 year olds which were above-average (0.33 and 0.31, respectively, compared with 0.25 for Scotland as a whole), but their rates for the 35-44 age-group did not stand out as much. However, the pattern was less clear for the 15-24 age-group, for which several areas had death rates which were above the overall average level for Scotland for the five years.

4.7 As mentioned in Section 3.5, Information Services Division (ISD) has estimated the numbers of problem drug users (aged 15-64) for parts of Scotland. Table HB5 provides those figures for NHS Board areas, with their '95% confidence intervals', each area's estimated drug-related death rate per 1,000 problem drug users, and the likely range of values for that figure; Figure 2 shows the rates and their confidence intervals (Section 3.5 gives more information about 95% confidence intervals and the calculation of the likely range of values; ISD did not publish an estimate for Orkney 'due to the potential risk of disclosure and to help maintain patient confidentiality'). For example, for Scotland as a whole, it is estimated that (between 2009 and 2013) there were, on average, 9.1 drug-related deaths per year per 1,000 problem drug users. One difference between the coverage of the two figures ('all ages' for deaths; '15-64' for problem drug users) should not matter much, as there are very few drug-related deaths of people aged 0-14 or 65+; another may matter for two areas (Greater Glasgow & Clyde and Lanarkshire): the ISD estimates are based on the boundaries that applied at that time, whereas the numbers of drug-deaths are based on the boundaries that have applied from 1st April 2014. The main consequence of the boundary changes was to transfer around 80,000 people from the Greater Glasgow & Clyde area to the Lanarkshire area (the numbers involved in all the other boundary changes were much smaller). It follows that ISD’s estimates of the numbers of problem drug users, being based on the boundaries that applied in 2009/10, are likely to be over-estimates for the new Greater Glasgow & Clyde area, and under-estimates for the new Lanarkshire area. Therefore, Table HB5's 'per 1,000 problem drug user' death rates are likely to be under-estimated for Greater Glasgow and Clyde, and over-estimated for Lanarkshire. The boundary changes are likely to have had little effect on the figures for other areas.

4.8 Among the more populous areas, this rate was lowest in Ayrshire & Arran (7.7) and highest in Fife and, apparently, Lanarkshire (both 10.8); the rate for Greater Glasgow & Clyde (8.3) appears to be below that for Scotland as a whole (9.1), but (as noted above) the figures for Greater Glasgow & Clyde and Lanarkshire will be affected by the 'mis-match' caused by the change in the boundaries. The table shows wide (in percentage terms) confidence intervals for some areas, particularly for the ones with relatively small populations. As a result, some areas have wide likely ranges of values for their death rates, including some of the more populous areas (for example, for Fife, the likely range of values for the drug-related death rate is from 9.9 to 11.5 per 1,000 problem drug users).

4.9 There is a much narrower (in percentage terms) range of values for NHS Board areas when drug-related death rates are calculated on this basis (which takes account of the number of people who put their lives at risk) than when they are calculated per 1,000 population (Table HB4). For example, the lowest drug-related death rate per 1,000 problem drug users was 6.3 (Dumfries & Galloway), and the highest was 12.8 (Borders), so the highest figure was roughly twice the lowest one. In contrast, the lowest drug-related death rate per 1,000 population was 0.04 (Orkney), and the highest was 0.15 (Greater Glasgow & Clyde), so the highest figure was roughly four times the lowest one.