Study Cohort Characteristics
A total of 2,589 women met study selection criteria and were included in the analysis (Figure 1).
Of these individuals, 120 (4.6%) women were classified as having CKD according to our primary definition. Table 1a displays the characteristics of the study cohort at the baseline study visit, both overall and stratified by CKD status. The mean age was 31.4 ± 8.3 years old and most women (44.3%) identified their heritage/ethnicity as Mexican, followed by Cuban (14.5%) and Puerto Rican (12.7%). Compared to those without CKD, women with CKD were older (35.1 vs 31.2 years old) and had a higher BMI (33.4 kg/m2 vs 29.3 kg/m2). Fewer women with CKD had received a high school diploma or more compared to those without CKD (65.7% vs 73.1%). Women with CKD had over three times the prevalence of diabetes (25.5% vs 7.0%) and over four times the prevalence of hypertension (30.7% vs 6.7%) compared to those without CKD. The average time between baseline and second study visit was 6.2 years for both groups.
Table 1a. HCHS/SOL Baseline Visit (2008-2011) Characteristics of All Reproductive Age Women and by CKD status
Characteristic
|
Overall
n = 2,589
|
Without CKD
n = 2,469
|
With CKD
n = 120
|
*Age (years)
|
31.4 ± 8.3
|
31.2 ± 8.3
|
35.1 ± 7.7
|
*BMI (kg/m2)
|
29.5 ± 7.1
|
29.3 ± 7.1
|
33.4 ± 7.4
|
Heritage/Ethnicity (%)
|
|
|
|
Central American
|
8.1
|
7.9
|
12.6
|
Cuban
|
14.5
|
14.7
|
9
|
Dominican
|
11.4
|
11.4
|
10.5
|
Mexican
|
44.3
|
44.1
|
47.3
|
Puerto Rican
|
12.7
|
12.6
|
14.6
|
South American
|
4.3
|
4.5
|
1
|
More than one
|
4.7
|
4.7
|
5
|
High school diploma or more (%)
|
72.8
|
73.1
|
65.7
|
Cigarette use (past or current) (%)
|
23.3
|
23.3
|
22.1
|
Alcohol use (past or current) (%)
|
77.6
|
77.8
|
74.3
|
*Diabetes (%)
|
7.8
|
7.0
|
25.5
|
*Hypertension (%)
|
7.8
|
6.7
|
30.7
|
Average systolic BP (mmHg)
|
108.5 ± 12.4
|
108.2 ± 12.0
|
115.9 ± 18.3
|
Average diastolic BP (mmHg)
|
68.6 ± 10.1
|
68.3 ± 9.8
|
74.8 ± 14.1
|
ACE-I/ARB at baseline visit (%)
|
3.5
|
2.7
|
20.2
|
Creatinine (mg/dL)
|
0.70 ± 0.1
|
0.70 ± 0.1
|
0.76 ± 0.3
|
*Estimated GFR (mL/min/1.73m2)
|
111.7 ± 16.2
|
112.0 ± 15.7
|
104.2 ± 24.7
|
*Urine albumin to creatinine ratio (mg/g)
|
6.7 (4.8-11.3)
|
6.5 (4.7-10.5)
|
77.6 (42.1- 284.7)
|
*Statistically significant (p< 0.05) difference between women without CKD and women with CKD
Data are mean ± standard deviation or percent except for urine albumin to creatinine ratio which is median (interquartile range)
Abbreviations: HCHS/SOL, Hispanic Community Health Study, Study of Latinos; BMI, body mass index; BP, blood pressure; ACE-I/ARB, angiotensin converting enzyme inhibitor/ angiotensin II receptor blocker; GFR, glomerular filtration rate
The majority (67.5%) of women with CKD met criteria for CKD based on persistently elevated UACR at both visits while 12.5% met criteria due to a eGFR < 60 ml/min/1.73m2 at both visits or an elevated UACR at one visit and low eGFR at another (Table 1b). An additional 20% were considered to have CKD through one of the expanded definitions.
Table 1b. Distribution of CKD measures: eGFR by albuminuria category at Visit 1 and Visit 2 in Reproductive Age Women in HCHS/SOL (N= 2,589)
Visit 1
|
UACR < 30 mg/g
|
UACR 30-300 mg/g
|
UACR > 300 mg/g
|
GFR > 60
|
2337
|
213
|
21
|
GFR 30- 60
|
9
|
3
|
3
|
GFR < 30
|
0
|
1
|
2
|
|
|
|
|
Visit 2
|
|
|
|
GFR > 60
|
2371
|
178
|
29
|
GFR 30- 60
|
2
|
2
|
3
|
GFR < 30
|
0
|
0
|
2
|
Missing eGFR
|
|
|
2
|
eGFR in mL/min/1.73m2
Abbreviations: CKD, chronic kidney disease; eGFR, estimated glomerular filtration rate; HCHS/SOL, Hispanic Community Health Study, Study of Latinos; UACR urine albumin to creatinine ratio
The median (interquartile range) UACR of those with CKD at the baseline visit was 77.6 (42.1- 284.7) mg/g and was 123.8 (36.4- 493.9) mg/g at the second visit compared to 6.5 (4.7-10.5) mg/g and 4.1 (2.5- 7.9) mg/g at baseline and second visit in those without CKD.
CKD and infertility, cessation of menses, and hysterectomy
Infertility was reported by 15.0% of women with CKD and 12.8% of women without CKD. Of those who responded to a follow-up question of the perceived cause of their infertility (n = 142), all women with CKD reported their infertility was due to either a medical problem in themselves or both themselves and their partner (vs. their partner alone). A small percentage of women without CKD (7.5%) reported their infertility was due to their partner alone. Cessation of menses was reported by 26.7% of women with CKD and 14.5% of women without CKD at similar mean (41.3 vs 41.8) and median (44 (37-47) vs 44 (39-47)) ages. Reasons cited for amenorrhea included “They stopped naturally” (44.3% of women with CKD vs 48.3% of women without CKD), “Surgery to remove ovaries or uterus” (26.0% CKD vs 38.9% without CKD), and “Other” (29.6% CKD vs 10.5% without CKD). A history of hysterectomy was reported by 7.1% of women with CKD and 6.1% of women without CKD.
Table 2 compares the prevalence odds ratios for self-reported infertility, cessation of menses, and hysterectomy in women with vs. without CKD. Compared to women without CKD, those with CKD did not have a significantly increased odds of infertility (adjusted OR 1.02, 95% CI 0.42 - 2.49). In a crude comparison, women with CKD had twice the odds of experiencing cessation of menses (OR 2.15, 95% CI 1.15 - 4.0) but this was attenuated and no longer significant after adjustment for age and BMI (OR 1.25, 95% CI 0.52 - 3.04). The odds of hysterectomy were not statistically different between women with vs. without CKD (OR 1.17, 95% CI 0.61 - 2.25) and an adjusted analysis was not performed due to the low number of events. In the sensitivity analyses, the prevalence odds ratios were higher for infertility, cessation of menses, and hysterectomy in women with CKD but the estimates were not substantially different from the base analysis and were not statistically significant (Table 2).
Table 2. Multivariable Adjusted Association Between CKD and Self-reported Infertility, Cessation of Menses, and Hysterectomy Among Reproductive Age Women in the HCHS/SOL
Primary analyses
|
|
|
Infertility
|
|
Cessation of Menses
|
|
Hysterectomy
|
Characteristic
|
n
|
Unadjusted
OR (95% CI)
|
Adjusteda
OR (95% CI)
|
|
Unadjusted
OR (95% CI)
|
Adjustedb
OR (95% CI)
|
|
Unadjusted
OR (95% CI)
|
Adjusted
OR (95% CI)
|
No CKD
|
2,469
|
Ref.
|
Ref.
|
|
Ref.
|
Ref.
|
|
Ref.
|
Ref.
|
CKD
|
120
|
1.20 (0.49 -2.95)
|
1.02 (0.42-2.49)
|
|
2.15 (1.15-4.00)
|
1.25 (0.52-3.04)
|
|
1.17 (0.61-2.25)
|
NA
|
Sensitivity analysesc
|
|
|
Infertility
|
|
Cessation of Menses
|
|
Hysterectomy
|
Characteristic
|
n
|
Unadjusted
OR (95% CI)
|
Adjusteda
OR (95% CI)
|
|
Unadjusted
OR (95% CI)
|
Adjustedb
OR (95% CI)
|
|
Unadjusted
OR (95% CI)
|
Adjusted
OR (95% CI)
|
No CKD
|
2,493
|
Ref.
|
Ref.
|
|
Ref.
|
Ref.
|
|
Ref.
|
Ref.
|
CKD
|
96
|
1.41 (0.54-3.69)
|
1.19 (0.46-3.10)
|
|
2.66 (1.36-5.20)
|
1.74 (0.66-4.61)
|
|
1.35 (0.66-2.77)
|
NA
|
Abbreviations: CKD, chronic kidney disease; HCHS/SOL, Hispanic Community Health Study, Study of Latinos; OR, odds ratio; CI, confidence interval; Ref, referent; NA, not applicable.
Adjusted OR for hysterectomy not performed due to a low number of events
a Adjusted for BMI
b Adjusted for age and BMI
c In the sensitivity analysis, CKD was defined as either a low eGFR (< 60 ml/min per 1.73 m2) or a urine albumin to creatinine ratio of > 30 mg/g on spot urine samples at both visits
CKD and pregnancy loss
At the second visit, 92.9% (n=112) of women with CKD and 85.4% (n=2165) of women without CKD reported a history of pregnancy (Figure 1). A total of 45.9% of women (42.3% of women with CKD and 46.1% of women without CKD) reported a history of nonviable loss. As shown in Table 3, the presence of CKD was not associated with an increased risk of a nonviable pregnancy loss (adjusted OR 0.89, 95% CI 0.53 - 1.48). The risk appeared to increase when assessing only those women who reported pregnancy occurring after baseline visit (adjusted OR 2.11, 95% CI 0.63 - 7.02) though this was imprecise and not statistically significant. A sensitivity analysis using the restricted CKD definition showed similar results (Table 3). In addition, we repeated our analyses excluding those with GFR < 60 ml/min per 1.73 m2 at either visit and noted similar results (data not shown).
Table 3. Association Between CKD and Nonviable Pregnancy Loss Among Reproductive Age Women in the HCHS/SOL
Primary analyses
|
|
Nonviable loss among women with history of pregnancy at any time (n=2277)
|
|
Nonviable loss among women reporting pregnancy after baseline visit (n=630)
|
|
Characteristic
|
Unadjusted
OR (95% CI)
|
Adjusteda
OR (95% CI)
|
|
Unadjusted
OR (95% CI)
|
Adjustedb
OR (95% CI)
|
|
No CKD
|
Ref.
|
Ref.
|
|
Ref.
|
Ref.
|
|
CKD
|
0.86 (0.52-1.43)
|
0.89 (0.53-1.48)
|
|
1.81 (0.56-5.90)
|
2.11 (0.63-7.02)
|
|
|
Sensitivity analysesc
|
|
Nonviable loss among women with history of pregnancy at any time (n=2277)
|
|
Nonviable loss among women reporting pregnancy after baseline visit (n=630)
|
|
|
Characteristic
|
Unadjusted
OR (95% CI)
|
Adjusteda
OR (95% CI)
|
|
Unadjusted
OR (95% CI)
|
Adjustedb
OR (95% CI)
|
|
No CKD
|
Ref.
|
Ref.
|
|
Ref.
|
Ref.
|
|
|
CKD
|
0.88 (0.49-1.60)
|
0.91 (0.50-1.66)
|
|
1.66 (0.43-6.36)
|
1.80 (0.48-6.81)
|
|
|
Abbreviations: CKD, chronic kidney disease; HCHS/SOL, Hispanic Community Health Study, Study of Latinos; OR, odds ratio; CI, confidence interval; Ref, referent.
a Adjusted for BMI
b Adjusted for Diabetes
c In the sensitivity analysis, CKD was defined as either a low GFR (< 60 ml/min per 1.73 m2) or a urine albumin to creatinine ratio of > 30 mg/g on spot urine samples at both visits