Research Article

Clinical Phenotype of Diabetic Peripheral Neuropathy and Relation to Symptom Patterns: Cluster and Factor Analysis in Patients with Type 2 Diabetes in Korea

Table 3

Comparison of the demographic and clinical characteristics and the clinical impacts of diabetic peripheral neuropathy on pain, sleep, and quality of life in three clustered groups in newly diagnosed patients ().

VariableCluster 1
()
Cluster 2
()
Cluster 3
()
value

Age, years64.3 ± 10.066.1 ± 9.764.6 ± 9.50.447
Female, n (%)89.0(58.6)33.0(48.5)32.0(71.1)0.058
Diabetes treatment, n (%)0.008
 Diet and exercise6 (4.0)1 (1.5)1 (2.2)
 OHA105 (69.1)34 (50.0)23 (51.1)
 Insulin14 (9.2)18 (26.5)7 (15.6)
 Insulin and OHA27 (17.8)15 (22.1)14 (31.1)
BMI, kg/m225.4 ± 3.524.5 ± 3.825.6 ± 4.20.276
FPG, mg/dL132.4 ± 41.3147.6 ± 51.6141.0 ± 76.10.260
HbA1c, %7.5 ± 1.47.9 ± 1.79.1 ± 9.80.121
HbA1c, mmol/mol59.0 ± 15.162.8 ± 18.176.3 ± 106.70.121
Hypertension101 (66.5)48 (70.6)27 (60.0)0.506
Dyslipidemia76 (50.0)36 (52.9)20 (44.4)0.675
Obesity4 (2.6)0 (0.0)3 (6.7)0.096
Diabetic retinopathy, n (%)27 (17.8)18 (26.5)8 (17.8)0.302
Diabetic nephropathy25 (16.5)16 (23.5)6 (13.3)0.311
MNSI score3.1 ± 1.23.9 ± 1.26.5 ± 1.9<0.001
Pain severity items
 Worst2.1 ± 2.75.0 ± 3.67.6 ± 2.5<0.001
 Weakest0.4 ± 0.81.3 ± 1.62.9 ± 2.2<0.001
 Average1.1 ± 1.53.1 ± 2.55.1 ± 2.3<0.001
Pain interference items
 General activity0.6 ± 1.53.2 ± 3.26.4 ± 2.9<0.001
 Mood1.1 ± 2.03.7 ± 3.26.8 ± 2.9<0.001
 Walking0.6 ± 1.53.0 ± 3.26.1 ± 3.2<0.001
 Normal work0.7 ± 1.52.9 ± 3.16.1 ± 3.3<0.001
 Relationship0.3 ± 1.01.7 ± 2.54.8 ± 3.7<0.001
 Sleep0.8 ± 1.82.1 ± 3.05.8 ± 3.4<0.001
 Enjoyment of life0.5 ± 1.32.3 ± 3.15.7 ± 3.7<0.001
Pain interference index4.0 ± 5.110.8 ± 7.919.4 ± 7.7<0.001
MOS-SS
 Sleep quantity4.3 ± 1.74.2 ± 1.82.7 ± 1.7<0.001
 Respiratory problem during sleep5.8 ± 0.75.8 ± 0.64.8 ± 1.7<0.001
 Sleep initiation problem4.6 ± 1.84.5 ± 1.72.6 ± 1.7<0.001
 Sleep maintenance problem4.4 ± 1.84.7 ± 1.62.7 ± 1.8<0.001
 Somnolence5.4 ± 1.05.3 ± 1.13.8 ± 1.7<0.001
 Sleep adequacy4.6 ± 1.64.5 ± 1.72.7 ± 1.8<0.001
Sleep problem index29.2 ± 5.928.9 ± 5.419.3 ± 5.8<0.001
EQ-5D§
 Mobility1.2 ± 0.41.8 ± 0.52.0 ± 0.5<0.001
 Self-care1.1 ± 0.31.2 ± 0.51.6 ± 0.7<0.001
 Usual activity1.1 ± 0.31.7 ± 0.52.0 ± 0.5<0.001
 Pain discomfort1.3 ± 0.52.0 ± 0.42.4 ± 0.6<0.001
 Anxiety/depression1.3 ± 0.51.6 ± 0.52.0 ± 0.6<0.001
EQ-5D index§6.0 ± 1.48.2 ± 1.210.0 ± 1.9<0.001
EQ-5D VAS74.2 ± 14.153.9 ± 16.741.4 ± 21.2<0.001
Medications for DPN
 None133 (87.5)55 (80.9)36 (80.0)0.298
 Antidepressants1 (0.7)3 (4.4)0 (0.0)0.071
 Anticonvulsants1 (0.7)1 (1.5)1 (2.2)0.653
α-Lipoic acid6 (4.0)4 (5.9)1 (2.2)0.622
γ-Linoleic acid1 (0.7)1 (1.5)2 (4.4)0.187
 Others10 (6.6)5 (7.4)5 (11.1)0.598

Data are expressed as means ± SD for continuous variables and frequency (%) for categorical variables. Items were derived from the BPI-SF. A 0–10 numeric rating scale was anchored at 0 for “no pain” and 10 for “pain as bad as you can imagine.” Item response on a 6-point scale ranging from 1 for “all of the time” to 6 for “none of the time;” dimensions of sleep quantity, “get the amount of sleep you needed;” and sleep adequacy, “get enough sleep to feel rested upon waking in the morning” were calculated backwards. §Items were from three levels indicating “no problem” (or 1), “some problems” (or 2), and “severe problems” (or 3), and EQ-5D index was the sum of scores of 5 dimensions. Values from 0 to 100, where 0 represents the worst imaginable health state and 100 represent the best imaginable health state. OHA: oral hypoglycemic agent(s); BMI: body mass index; FPG: fasting plasma glucose; MNSI: Michigan Neuropathy Screening Instrument questionnaire; MOS-SS: medical outcomes study sleep scale; EQ-5D: EuroQol, 5-dimensions; VA: visual analog scale.