Sodium depletion and secondary hyperaldosteronism in outpatients with an ileostomy: a cross-sectional study

Figures & data

Table 1. Participant characteristics.

Characteristics	n	Summary
Age, year, median (IQR, range)	49	60 (51–67, 32–78)
Female % (95% CI)	30	61% (47–74%)
Indication for ileostomy formation, % (95% CI)	49
Inflammatory bowel disease	41	83% (70–92%)
Ulcerative colitis	33	67% (53–79%)
Crohn’s disease	8	16% (8–30%)
Colorectal cancer	2	4% (1–15%)
Miscellaneous	6	12% (6–25%)
Chronic obstipation	3	6% (2–18%)
Familial adenomatous polyposis	2	4% (1–15%)
Incarcerated ventral hernia	1	2% (0.3–14%)
Years with ileostomy, y, median (IQR, range)	49	5 (2–13, 0–46)
Estimated bowel length, cm, median (IQR, range)	49	350 (310–350, 230–350)
End-ileostomy with complete small bowel	32	350
End-ileostomy after previous pouch	8	310
End-ileostomy after ileal resections	9	300 (250–315, 230–340)
Hand grip strength, kg, mean (SD)	48	34.3 (±10.1)
Female	29	29.2 (±6.1)
Male	19	42.1 (±10.1)
BMI, kg/m^2, median (IQR, range)	46	25.7 (23.3–28.9, 18.6–40.1)
Female	28	26.0 (22.5–29.2, 18.6–37.3)
Male	18	25.7 (24.5–27.3, 20.5–40.1)
Weight, kg, median (IQR, range)	46	80 (69–89, 53–127)
Female	28	77 (63.83, 53–107)
Male	18	86 (78–92, 57–127)
Height, cm, mean (SD)	46	173 (±7)
Female	28	169 (±4)
Male	18	180 (±6)
Waist, cm, mean (SD)	46	94 (±16)
Female	28	90 (±17)
Male	18	100 (±13)
FFMI, kg/m^2, mean (SD)	46	16.7 (±2.1)
Female	28	15.4 (±1.4)
Male	18	18.6 (±1.5)
TBW L, mean (SD)	46	37.7 (±6.6)
Female	28	33.5 (±3.8)
Male	18	44.3 (±4.4)
Resistance, Ω, mean (SD)	46	615 (±77)
Female	28	657.9 (±60)
Male	18	548.7 (±47)
Stoma-QoL, mean (SD)	45	61.4 (±9.9)
EQ5D5L index, median (IQR, range)	49	0.80 (0.68–0.87, 0.44–1.00)
EQ5D5L VAS, median (IQR, range)	47	74 (60–90, 22–100)
Depressed, diagnosed with MDI, % (95% CI)	47	15% (7 -29%)

Notes: Bowel length was estimated to be 350 cm if a patient’s remaining gut was not measured following colectomy. Forty centimetre was subtracted if they had previously had an ileo-anal reservoir (pouch). Resistance is an estimate of hydration (TBW) measured with bioelectrical impedance analysis without using prediction equations. Stoma-QoL is a stoma-specific Quality-of-Life-questionnaire. EQ5D5L is a generic health-related Quality-of-Life-questionnaire. The Major Depression Inventory (MDI) is a diagnostic instrument for assessing depression.

FFMI: fat-free mass index; TBW: total body water.

Figure 1. Urinary sodium excretion in 49 patients with an ileostomy, measured in a morning or midday spot urine sample. Circles indicate patients with end-ileostomy and complete small bowel, squares indicate patients with end-ileostomy after a previous pouch, and triangles indicate patients with end-ileostomy and ileal resections. Open marks indicate U-Na values ≤ 20 mmol/L, and closed marks indicate U-Na values >20 mmol/L. U-Na: urinary sodium.

Table 2. Categorisation of patients with and without measurable natriuresis.

	U-Na >20 mmol/L	U-Na ≤20 mmol/L	Total	p Value
P-Aldosterone ≤1197 pmol/L	27 (75%%)	9 (25%)	36 (100%)
P-Aldosterone >1197 pmol/L	0 (0%)	13 (100%)	13 (100%)
Total	27	22	49
				p < .001
Normal P-CO2	24 (61.5%)	15 (38.5%)	39 (100%)
Low P-CO2	3 (30%)	7 (70%)	10 (100%)
Total	27	22	49
				p = .090
eGFR >90 ml/min/1,73 m^2	13 (76%)	4 (24%)	17 (100%)
eGFR ≤90 ml/min/1,73 m^2	14 (44%)	18 (56%)	32 (100%)
Total	27	22	49
				p = .038
P-creatinine normal	26 (60%)	17 (40%)	43 (100%)
P-creatinine high	1 (17%)	5 (83%)	6 (100%)
Total	27	22	49
				p = .077
No previous pouch	26 (63%)	15 (37%)	41 (100%)
Previous pouch	1 (12.5%)	7 (87.5%)	8 (100%)
Total	27	22	49
				p = .016
Complete small bowel	4 (24%)	13 (76%)	17 (100%)
Not complete small bowel	23 (72%)	9 (28%)	32 (100%)
Total	27	22	49
				p = .002

Notes: High/low values were based on reference range values. ‘Not complete small bowel’ was assigned to patients with an end-ileostomy and any small bowel resection.

U-Na: urinary sodium excretion; P: plasma; CO₂: carbon dioxide; eGFR: estimated glomerulus filtration rate.

Figure 2. Comparison of paraclinical variables in patients with and without measurable natriuresis. Dotted lines indicate reference values. Circles indicate patients with end-ileostomy and complete small bowel, squares indicate patients with end-ileostomy after a previous pouch, and triangles indicate patients with end-ileostomy and ileal resections. Open marks indicate U-Na values ≤20 mmol/L, and closed marks indicate U-Na values >20 mmol/L. CO₂: carbon dioxide; eGFR: estimated glomerulus filtration rate; BUN: blood urea nitrogen; P: plasma; U-Na: urinary sodium.

Figure 3. Correlations between different dehydration assessment methods. Resistance is an estimate of hydration (TBW) measured with bioelectrical impedance analysis. Grey marks are not included in the analysis. Circles indicate patients with end-ileostomy and complete small bowel, squares indicate patients with end-ileostomy after a previous pouch, and triangles indicate patients with end-ileostomy and ileal resections. Open marks indicate u-Na values ≤20 mmol/L, and closed marks indicate u-Na values >20 mmol/L. BUN: blood urea nitrogen; P: plasma; U-Na: urinary sodium; TBW: total body water.

Figure 4. Dietary intake and association with urinary sodium. Comparison of patients with ileostomy who (a) added table salt to their diet or not, (b) ingested psyllium husks or not, (c) had an intake of fruit under or above 100 g/d and (d) had an intake of vegetables under or above 100 g/d. Circles indicate patients with end-ileostomy and complete small bowel, squares indicate patients with end-ileostomy after a previous pouch, and triangles indicate patients with end-ileostomy and ileal resections. Open marks indicate u-Na values ≤ 20 mmol/L, and closed marks indicate U-Na values >20 mmol/L. U-Na: urinary sodium excretion.