Association of comorbidities with increasing severity of peripheral neuropathy in diabetes mellitus

Table 1 Blood testing performed for identification of comorbidities

Blood test	Normative range
Red blood cell counts
Women	4.0-5.6 × 1012/L
Men	4.5-6.0 × 1012/L
White blood cell counts	4.0-11.0 × 109/L
Platelet counts	150-400 × 109/L
Electrolytes (mmol/L)
Sodium	133-145
Potassium	3.3-5.1
Chloride	98-111
Bicarbonate	21-31
Calcium	2.10-2.55
Magnesium	0.65-1.05
Urea (mmol/L)	3.0-8.5
Creatinine (μmol/L)	50-120
Aspartate transaminase (U/L)	8-40
Alanine transaminase (U/L)	1-60
Gamma glutamyl-transferase (U/L)	8-40
Albumin (g/L)	33-48
Total bilirubin (μmol/L	0-20
Total cholesterol (mmol/L)	3.8-5.2
Low density lipoproteins (mmol/L)	2.2-3.4
High density lipoproteins (mmol/L)	> 0.9
Triglycerides (mmol/L)	0.6-2.3
Cobalamin (measured by immunoassay), (pmol/L)	> 155
Thiamine (μg/L)	33-110
Thyroid stimulating hormone (mU/L)	0.2-6.0
Total thyroxine (nmol/L)	59-154
Antinuclear autoantibody detection	≤ 1:80
Extractable nuclear antigens	Absent
Serum protein electrophoresis	The sensitivity for detection of gammopathy was 2 g/L with serum protein electrophoresis, and samples with peaks of 2-4 g/L were subjected to immunofixation for verification
Serum copper (μmol/L)	11-24
Fasting methylmalonic acid (measured using high performance liquid chromatography), (μmol/L)	< 0.15
Hemoglobin A1C	4.3%-6.1%

Normative data was supplied by the laboratory that performed all related testing-Calgary Laboratory Services in Calgary, Alberta, Canada. Normative data is presented as a range based upon 95%CI.

Table 2 Demographics for cohorts with diabetes mellitus n (%)

	Type 1 diabetes only	Type 1 diabetesplus comorbidity	Type 2 diabetesonly	Type 2diabetes plus comorbidity
Patients	31	19	228	91
Duration of disease (mo)	316 ± 26	310 ± 25	107 ± 7	150 ± 12a
HbA1c level (%)	11.2 ± 1.4	11.7 ± 1.6	9.8 ± 0.2	11.2 ± 0.3a
Age (yr)	50 ± 7	54 ± 8	62.0 ± 1.8	61.0 ± 1.4
Sex (male)	17 (55)	12 (63)	91 (40)	36 (40)
	Nature of comorbidities	15 (79)		63 (69)
	lipid disorder
	Low cobalamin/elevated MMA	9 (47)		36 (40)
	Monoclonal gammopathy	2 (11)		4 (4)
	Thyroid disease	5 (26)		11 (12)
	Uremia	7 (37)		13 (14)
	Autoimmune diseases	4 (21)		8 (9)
	Alcoholism	3 (16)		10 (11)
	Hypertension	13 (68)		74 (81)
Medications
Insulin	31 (100)	19 (100)	55 (23)	24 (26)
Metformin			198 (86)	80 (88)
Glyburide			155 (68)	63 (69)
Gliclazide			41 (18)	11 (12)
Statins/Ezetemide	21 (68)	9 (47)	146 (64)	48 (53)
Blood pressure medications	22 (71)	14 (74)	118 (52)	57 (62)
Thyroid replacement	12 (39)	5 (26)	38 (17)	14 (15)
SSRIs	4 (13)	2 (11)	28 (12)	16 (18)
Anxiolytics/Sedatives	8 (26)	3 (16)	48 (21)	13 (14)
NSAIDs	12 (39)	9 (47)	104 (46)	55 (60)
Acetaminophen	6 (19)	3 (16)	37 (16)	17 (19)
Gabapentin	5 (16)	4 (21)	41 (18)	15 (16)
Pregabalin	4 (13)	3 (16)	36 (16)	11 (12)
Codeine	3 (10)	4 (21)	31 (13)	8 (9)
Amitriptyline	3 (10)	3 (16)	25 (11)	6 (7)
Oxycocet	1 (3)	2 (11)	18 (8)	4 (4)
Nortriptyline	1 (3)	1 (5)	12 (5)	4 (4)
Duloxetine	2 (6)	3 (16)	22 (10)	5 (5)
Venlafaxine	3 (10)	2 (11)	25 (11)	4 (4)
Fentanyl	1 (3)	2 (11)	6 (3)	3 (3)
Tramadol	1 (3)	0 (0)	8 (3)	2 (2)
Morphine	0 (0)	2 (11)	7 (3)	3 (3)

^aP < 0.05 vs type 2 diabetes only and type 2 diabetes plus comorbidity cohort. MMA: Methylmalonic acid; SSRIs: Selective serotonin reuptake inhibitors; NSAIDs: Nonsteroidal antiinflammatory drugs.