FIDELIS CHYMICORUM TURBA IN HANC URNAM

Thirty-four deaths for which cause could not be assigned in the survey are excluded from analysis in this section; this left 271 deaths for each of which a cause was assigned by both the DSS and the survey. The percentage distribution of 271 deaths according to cause-of-death classification systems is presented in Table 6.2.

Table 6.2 Percentage distribution of maternal deaths according to cause-of-death classification systems. Classification system Cause-of-death category DSS Survey (N=271) (N=271) Spontaneous abortion 5.2 7.7 Induced abortion 9.2 6.3 Haemorrhage 25.8 27.3 Toxaemia or eclampsia 15.5 14.8 Obstructed labour or prolonged labour 7.7 7.4

Other direct obstetric deaths 15.9 14.8 Gastro-intestinal complications 8.5 11.4

Accidental death 5.9 7.4

Other indirect obstetric deaths 5.5 3.0

Total 100.0 100.0

The percentage distributions of death by cause assigned by the two systems seem to be remarkably similar. Are they statistically similar too? To answer this question, we examine fully the hypothesis of no difference in the distribution of cause of death as measured by the DSS

and the survey. Using the DSS proportions as the expected distributions, the X 2 goodness of fit statistic is 11.32 with df=8 suggesting that the distribution of survey cause of death is identical with the distribution of DSS cause of death. This does not mean, however, that differences at the individual level are not significant.

Even comparing the percentage distribution of cause of 384 deaths assigned by the DSS with those of 305 deaths assigned by the survey, the distributions look similar except for the induced abortion and unknown causes (Table 6.3). This provides very strong evidence that the sisterhood method produces reasonable information on cause of maternal death except for induced abortion.

Table 6.3 Percentage distribution of maternal deaths according to cause-of-death classification systems. Cause-of-death category Classification system DSS Survey (N=384) (N=305) Spontaneous abortion 4.4 6.9 Induced abortion 18.2 5.6 Haemorrhage 20.1 24.3 Toxaemia or eclampsia Obstructed labour or 12.8 13.1 prolonged labour 6.0 6.6

Other direct obstetric deaths 16.9 13.1 Gastro-intestinal complications 7.6 10.2

Accidental death 7.6 6.6

Other indirect obstetric deaths 5.5 2.6

Unknown 1.0 11.1

To see how the two systems vary in classifying cause of specific deaths, the rate of agreement between causes of death classified by the systems are presented in Table 6.3. The rate of agreement of the survey cause with the DSS cause is the number of deaths in the same category in both systems divided by the number of deaths in the category in the DSS classification. This definition of rate of agreement was used by Grubb et a l . (1988:386).

Table 6.4 Per cent agreement between causes of death for the DSS and the survey.

Cause-of-death category

Death Same cause of death Agreement (%) Alla 271 222 81.9 Direct deathsb 176 152 86.4 Indirect deathsc 54 41 75.9 Abortiona 41 29 70.7

Note: aBased on the categories presented in Table 6.2. blnclude haemorrhage, toxaemia or eclampsia,

obstructed labour or prolonged labour, and other direct obstetric deaths.

clnclude gastro-intestinal, accidental, and other indirect obstetric deaths.

dlnclude induced and spontaneous abortion-related deaths.

As can be seen from Table 6.3, the rate of agreement between DSS cause and survey cause varies according to the type of calculation involved with it. Of the deaths for each of which a cause was assigned by both the DSS

and the survey, the overall rate of agreement is 82 per cent when the calculation is based on the nine broad categories of DSS cause of death shown in Table 6.2.

The agreement, however, would be 7 9 per cent (not shown in Table 6.3), as given by the statistic Kappa, which measures the degree of agreement between the two classification systems after removing the number of cases that would be expected to agree by chance. The difference between these two measures of agreement is trivially small.

For the direct obstetric deaths as a group, the agreement (not based on Kappa) is 86 per cent, while it is around 7 6 per cent for indirect obstetric deaths and 71 per cent for abortion-related deaths. The rates of agreement in this study are lower than the percentage agreement for deaths due to maternal causes, 94 per cent, that was found in an Egyptian study (Grubb et a l ., 1988:386) which compared causes of death classified by two independent systems. This lower rate could be explained by the two factors, namely sources of information used and the time elapsed between the death and the survey, which have already been discussed in Section 6.4 of this Chapter.

A more detailed picture of the rate of agreement, based on the nine broad DSS cause categories, is presented in

Table 6.5. The percentage of deaths for which causes are misclassified in the survey is also shown in this table.

Table 6.5 Distribution of DSS cause-of-death category classification by the survey cause-of-death category classification (N=271)

DSS Survey

Sp Ind Haem Tox OL OD GI Acc OIN Total death Sp 75.0 - - - 12.5 12.5 16 Ind 32.0 68.0 - - - 25 Haem - 91.4 - - _2.9 1.4 4.3 70 Tox - 2.4 88.1 - 4.8 4.8 - 42 OL - - - 95.2 4.8 - - 21 OD 2.3 - 16.3 4.7 - 72.1 4.7 - 43 GI - 4.3 - - 8.7 87.0 - 23 Acc - 6.3 - - - - _87.5 6.3 16 OIN - - 6.7 - 13.3 26.7 6.7 46.7 15 UK Note: Sp Ind Haem Tox OL OD GI Acc OIN Spontaneous abortion, Induced abortion, Haemorrhage, Toxaemia, Obstructed labour,

Other direct obstetric deaths, Gastro-intestinal,

Accidental,

Other indirect obstetric deaths.

Of the nine cause-of-death categories, the percentage agreement between the two classification systems is highest for deaths due to obstructed labour or prolonged