Where to Initiate Basal Insulin Therapy: Inpatient or Outpatient Department? Real-World Observation in China

Figures & data

Figure 1 Flow of patients included in the analysis. Patients ever admitted to hospital or lost to follow-up after insulin therapy initiation during 6-month study period were excluded.

Table 1 Baseline Characteristics of Inpatients and Outpatients Initiated with Basal Insulin

Characteristics	Overall N=14860	Inpatients N=8129	Outpatients N=6731	p value
Demographics
Male, n (%)	7873 (53.0)	4408 (54.2)	3465 (51.5)	0.001
Age (years), mean ± SD	55.3 ± 10.3	55.7 ± 10.3	54.8 ± 10.3	<0.001
Education (senior high school or higher), n (%)	6406 (43.1)	3631 (44.7)	2775 (41.2)	<0.001
Urban residence, n (%)	10,119 (68.1)	5689 (70.0)	4430 (65.8)	<0.001
Hospital levels, n (%)
Secondary hospitals	7774 (52.3)	4437 (54.6)	3337 (49.6)	<0.001
Tertiary hospitals	7086 (47.7)	3692 (45.4)	3394 (50.4)
Out-of-pocket ratio (%), mean ± SD	41.5 ± 27.1	35.9 ± 22.4	48.3 ± 30.5	<0.001
BMI (kg/m^2), mean± SD	24.8 ± 3.4	24.8 (3.4)	24.8 (3.3)	0.962
Diabetes duration (years), mean ± SD	6.4 ± 5.2	6.4 ± 5.4	6.4 ± 5.1	0.391
HbA1c (%), mean ± SD	9.6 ± 2.0	9.8 ± 2.1	9.3 ± 1.8	<0.001
HbA1c ≥ 9%, n (%)	8015 (53.9)	4692 (57.7)	3323 (49.4)	<0.001
FPG level (mmol/L), mean ± SD	11.6 ± 4.0	11.7 ± 4.3	11.5 ± 3.5	<0.001
Complication in the past (Yes), n (%)	5327 (35.9)	3480 (42.8)	1847 (27.4)	<0.001
Numbers of OADs ≥2, n (%)	8003 (53.9)	3902 (48.0)	4101 (60.9)	<0.001
OAD treatment duration (years), mean ± SD	5.6 ± 5.0	5.5 ± 5.1	5.8 ± 4.9	0.006
Participants experienced hypoglycaemia in the past 1-month (Yes), n (%)	801 (5.4)	437 (5.4)	364 (5.4)	0.931
Insulin initiation at baseline
Basal-only insulin, n (%)	11,282 (75.9)	5276 (64.9)	6006 (89.2)	<0.001
Basal-bolus insulin, n (%)	3578 (24.1)	2853 (35.1)	725 (10.8)	<0.001
Total dose of insulin (IU), mean ± SD	17.4 (12.5)	19.9 (14.2)	14.3 (9.3)	<0.001

Abbreviations: BMI, body mass index; FPG, fasting plasma glucose; OAD, oral antidiabetic drugs.

Figure 2 Evolution of insulin therapy after 6-month follow-up for inpatient and outpatient initiation. (A) Treatment transition after 6 months among all patients. (B) Treatment transition after 6 months among patients initiated with basal insulin alone. (C) Treatment transition after 6 months among patients initiated with basal-bolus insulin.

Figure 3 Proportion achieving HbA1c <7% between patients persistent or nonpersistent to initial insulin therapy after 6 months.

Note: 60 patients were not included in the analysis due to no results after 6 months. *Odds ratios were adjusted for region, patient resource (inpatient or outpatient initiation), age, gender, education, residence, hospital levels, disease duration, BMI, initiation with basal only or basal-bolus insulin and baseline HbA1c levels.

Table 2 Subgroup Analysis of Proportion Achieving HbA1c <7% Among Persistent and Nonpersistent Groups Between Inpatient Initiators and Outpatient Initiators After 6 Months

Baseline Characteristics Before Insulin Initiation	Patients Persistent to Initial Insulin Therapy		Adjusted Odds Ratio*	p value	Patients Nonpersistent to Initial Insulin Therapy		Adjusted Odds Ratio*	p value
	Inpatient Initiators N=5196^†	Outpatient Initiators N=5269^†			Inpatient Initiators N=2898^†	Outpatient Initiators N=1437^†
Overall	46.3 (44.9–47.6)	39.5 (38.2–40.9)	1.34 (1.23–1.47)	<0.001	37.3 (35.6–39.1)	36.2 (33.7–38.7)	1.03 (0.88–1.20)	0.723
HbA1c≥9%	36.8 (35.0–38.6)	28.2 (26.4–29.9)	1.37 (1.20–1.56)	<0.001	33.0 (30.9–35.1)	27.2 (24.2–30.4)	1.25 (1.01–1.55)	0.038
HbA1c<9%	57.2 (55.2–59.2)	50.0 (48.1–51.9)	1.26 (1.12–1.43)	<0.001	45.5 (42.4–48.6)	47.0 (43.2–50.9)	0.85 (0.68–1.06)	0.146
Complication (Yes)	43.6 (41.6–45.7)	37.0 (34.6–39.6)	1.41 (1.21–1.64)	<0.001	31.4 (28.8–34.1)	32.5 (27.9–37.5)	0.87 (0.66–1.16)	0.353
Complication (No)	48.3 (46.5–50.1)	40.5 (38.9–42.1)	1.31 (1.18–1.47)	<0.001	41.5 (39.2–43.9)	37.5 (34.6–40.4)	1.18 (0.99–1.42)	0.071
OAD number ≥ 2	43.8 (46.5–50.1)	35.9 (34.3–37.6)	1.45 (1.29–1.64)	<0.001	33.6 (31.1–36.1)	30.2 (27.1–33.5)	1.10 (0.88–1.37)	0.402
OAD number =1	48.6 (46.7–50.5)	45.5 (43.3–47.7)	1.16 (1.01–1.32)	0.033	40.8 (38.3–43.3)	43.8 (40.0–47.7)	0.94 (0.76–1.16)	0.551

Notes: ^†60 patients in total were not included in the analysis due to no HbA1c data at 6-month follow-up. *Odds ratios were adjusted for region, age, gender, education, residence, hospital levels, disease duration, BMI, initiation with basal only or basal-bolus insulin and baseline HbA1c levels.

Abbreviation: OAD, oral antidiabetic drugs.

Table 3 Comparison of Proportion Achieving HbA1c <7% After 6 Months Between Inpatient and Outpatient Insulin Initiation by HOC Level Among Patients Persisting with Initial Insulin Therapy

HOC Level	Inpatient (N=5196)		Outpatient (N=5269)		Adjusted Odds Ratio*	p value
	n	HbA1c<7% rate, % (95% CI)	n	HbA1c<7% rate, % (95% CI)
3	600	32.7 (29.0–36.5)	457	19.0 (15.7–22.9)	2.06 (1.49–2.86)	<0.001
2	1856	39.9 (37.7–42.2)	1849	33.6 (31.5–35.8)	1.31 (1.12–1.52)	0.001
1	2043	50.9 (48.7–53.0)	2208	42.1 (40.0–44.1)	1.47 (1.28–1.68)	<0.001
0	697	61.4 (57.7–65.0)	755	58.9 (55.4–62.4)	0.96 (0.76–1.21)	0.726

Notes: HOC: The HbA1c, oral antidiabetic drugs and complication (HOC) level reflected patients’ condition at baseline and was calculated based on HbA1c level (HbA1c≥9% scored as one and HbA1c <9% as zero) plus OADs numbers (OAD numbers ≥2 scored as one and OAD number = 1 as zero) and complications before insulin initiation (having complications in the past scored as one and without complication in the past as zero). *Odds ratios were adjusted for region, age, gender, education, residence, hospital levels, disease duration, BMI, initiation with basal only or basal-bolus insulin and baseline HbA1c levels.