When is diabetes distress clinically meaningful?: establishing cut points for the Diabetes Distress Scale.
OBJECTIVE
To identify the pattern of relationships between the 17-item Diabetes Distress Scale (DDS17) and diabetes variables to establish scale cut points for high distress among patients with type 2 diabetes.


METHODS
Recruited were 506 study 1 and 392 study 2 adults with type 2 diabetes from community medical groups. Multiple regression equations associated the DDS17, a 17-item scale that yields a mean-item score, with HbA(1c), diabetes self-efficacy, diet, and physical activity. Associations also were undertaken for the two-item DDS (DDS2) screener. Analyses included control variables, linear, and quadratic (curvilinear) DDS terms.


RESULTS
Significant quadratic effects occurred between the DDS17 and each diabetes variable, with increases in distress associated with poorer outcomes: study 1 HbA(1c) (P < 0.02), self-efficacy (P < 0.001), diet (P < 0.001), physical activity (P < 0.04); study 2 HbA(1c) (P < 0.03), self-efficacy (P < 0.004), diet (P < 0.04), physical activity (P = NS). Substantive curvilinear associations with all four variables in both studies began at unexpectedly low levels of DDS17: the slope increased linearly between scores 1 and 2, was more muted between 2 and 3, and reached a maximum between 3 and 4. This suggested three patient subgroups: little or no distress, <2.0; moderate distress, 2.0-2.9; high distress, ≥3.0. Parallel findings occurred for the DDS2.


CONCLUSIONS
In two samples of type 2 diabetic patients we found a consistent pattern of curvilinear relationships between the DDS and HbA(1c), diabetes self-efficacy, diet, and physical activity. The shape of these relationships suggests cut points for three patient groups: little or no, moderate, and high distress.
Department of Family & Community Medicine, University of California, San Francisco, San Francisco, California, USA. fisherl@fcm.ucsf.edu
Lawrence
L
Fisher
Danielle M
DM
Hessler
William H
WH
Polonsky
Joseph
J
Mullan
D000368:Aged; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology* / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013315:Stress, Psychological / Q000175:diagnosis* / Q000503:physiopathology*