Psychosocial predictors of metabolic instability in brittle diabetes - A multivariate time series analysis

The term "brittle diabetes" denotes the unstable course of an insulin-dependent diabetes characterised by frequent hypo- or hyperglycaemic crises. The aim of this study is to demonstrate empirically how psychosocial parameters interact with metabolic instability in a paradigmatic case of juvenile brittle diabetes. By means of a structured diarystudy, blood sugar values, moods (SAM), body symptoms (GBB), the daily hustle and hassle, helping therapeutic alliance (HAQ) and the aspects of setting were registered. Resulting time series (112 days each) were ARIMA-analysed by a multivariate approach. It could be shown that the mean variance of daily blood sugar values as an indicator of brittleness was predicted by moods, body complaints and by a family session as setting factor (p < 0.05, for corresponding predictors). Feelings of dominance preceded an increase of blood sugar variance, whereas depressive moods, anger and body symptoms were associated with metabolic instability. A family therapy session also resulted in an increase of the mean blood sugar variance. The model accounted for almost 30% of the total variance of the dependent variable (R-square-adjusted, p < 0.0001). The potential of multivariate time-series as a means to demonstrate psychosomatic interrelations is discussed. We believe that the results may also contribute to an empirically rooted understanding of psychodynamic processes in psychosomatoses.