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 1 April 2014. The figures for earlier years show what the numbers would have been, had the new boundaries applied in those years. Table HB1 shows the numbers of drug-related deaths for each NHS Board area. Of the 613 deaths in 2014, 189 (31 per cent) were in the Greater Glasgow & Clyde NHS Board area. Lothian, with 105 (17 per cent), had the next highest total followed by Lanarkshire (67 or 11 per cent), Tayside (48 or 8 per cent), Fife (46 or 8 per cent), and Ayrshire & Arran (43 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 Greater Glasgow & Clyde: 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 2000-2004 and 2010-2014 were Lothian (up by 45, from 41 to 86), Greater Glasgow & Clyde (up by 38, from 133 to 171), Lanarkshire (up by 33, from 33 to 66), Tayside (up by 26, from 18 to 44), Fife (up by 25, from 13 to 38), Ayrshire & Arran (up by 15, from 25 to 40), Highland (up by 13, from 9 to 22) and Forth Valley (up by 12, from 13 to 25).

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 2010-2014) 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 558 drug-related deaths per year represented a rate of 0.11 per 1,000 population. The area with the highest rate was Greater Glasgow & Clyde (0.15); next highest were Ayrshire & Arran and Tayside, both of which had rates of 0.11. Finally, the lower part of the table shows the number of ‘extra’ deaths that would be counted, for each area, in the consistent series (see paragraph 2.9 and Annex F). As all the figures are relatively small, it is clear that the use of the consistent series would not change markedly the level of, or the trend in, the number of drug-related deaths for any area.

4.4 Table HB2 gives a breakdown by cause of death for each NHS Board area for 2014. 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, 50 per cent of the total number of drug-related deaths in 2014, and the figures for all the most populous areas were not too far from this level (each was between 40 per cent and 60 per cent). Methadone was implicated in, or potentially contributed to, 35 per cent of drug-related deaths overall; with unusually high proportions in Ayrshire & Arran (24 out of 43) and Lothian (51 out of 105) and rather low proportions in Highland (3 out of 25) and Forth Valley (5 out of 25). The table also shows that benzodiazepines were implicated in, or potentially contributed to, a high proportion of drug-related deaths in Grampian (20 out of 36) and a low proportion in Greater Glasgow & Clyde (20 out of 189), compared to 20 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 2010-2014), 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 for the three oldest of the five age-groups for which figures are provided: 0.43 for 35-44 year olds, 0.22 for the 45-54 age-group, and 0.08 for the 55-64 age-group; all well above the overall average rates for Scotland as a whole for the same 5-year period (0.27, 0.14 and 0.05 respectively). Fife and Tayside had rates for 25-34 year olds which were clearly above-average (0.32 and 0.29, respectively, compared with 0.24 for Scotland as a whole), and Ayrshire & Arran had the highest rate for 15-24 year olds (0.11, compared with 0.07 for Scotland as a whole).

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 per cent 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 per cent confidence intervals and the calculation of the likely range of values. For example, for Scotland as a whole, it is estimated that (between 2010 and 2014) there were, on average, 9.4 drug-related deaths per year per 1,000 problem drug users. The difference between the coverage of the two figures ('all ages' for deaths; '15-64' for problem drug users) should not matter much, as Table 4 showed there are relatively few drug-related deaths of people aged 0-14 or 65+.

4.8 Among the more populous areas, this rate was lowest in Forth Valley (8.0) and highest in Fife (13.2) and Highland (10.8); the rate for Greater Glasgow & Clyde (9.0) is below that for Scotland as a whole (9.4). 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 11.3 to 14.8 per 1,000 problem drug users).

4.9 There is a narrower (in percentage terms) range of values for the ‘mainland’ 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. For example, Table HB5 shows that the lowest drug-related death rate per 1,000 problem drug users was 7.1 (Dumfries & Galloway), and the highest was 13.2 (Fife), so the highest figure was less than twice the lowest one. In contrast, in Table HB4, the lowest drug-related death rate per 1,000 population was 0.06 (Dumfries & Galloway), and the highest was 0.15 (Greater Glasgow & Clyde), so the highest figure was two-and-a-half times the lowest one. (The 'island' areas are excluded from such comparisons because their relatively small numbers may lead to large percentage fluctuations in their rates.)