Iodine status in Danish pregnant and breastfeeding women including studies of some challenges in urinary iodine status evaluation

Denmark was previously iodine deficient with regional differences. Moderate iodine deficiency appeared in West Denmark and mild iodine deficiency in East Denmark and also Danish pregnant and breastfeeding women suffered from iodine deficiency. The Danish mandatory iodine fortification of salt was introduced in the year 2000 and has increased iodine intake in the Danish population. However, median urinary iodine concentration in the general population and in pregnant and breastfeeding women is still below the level recommended, corresponding to mild iodine deficiency. Certain characteristics may challenge the evaluation of urinary iodine status in pregnancy and during breastfeeding. This review also addresses methodological challenges related to spot urine sampling conditions and the use of iodine supplement and discusses the use of non-pregnant population groups as a proxy for iodine intake in pregnant women.

Challenges in the evaluation of urinary iodine status in pregnancy: the importance of iodine supplement intake and time of sampling

OBJECTIVES

Median urinary iodine concentration (UIC) is the recommended method to evaluate iodine status in pregnancy, but several factors may challenge the interpretation of the results. We evaluated UIC in pregnant women according to (1) sampling in the hospital versus at home, (2) time of the most recent iodine supplement intake prior to sampling, and (3) members of their household.

STUDY DESIGN

Danish cross-sectional study in the year 2012. Pregnant women (n = 158), their male partners (n = 157) and children (n = 51) provided a questionnaire with detailed information on iodine supplement intake and a spot urine sample obtained in the hospital and/or at home for measurement of UIC and urinary creatinine concentration.

RESULTS

In the pregnant women providing a urine sample both in the hospital and at home (n = 66), individual UIC (p = 0.002) and urinary creatinine concentration (p = 0.042), but not estimated 24-hour urinary iodine excretion (p = 0.79), were higher when sampling was at home. Median UIC was dependent on the time of the most recent iodine supplement intake prior to sampling [same day (n = 79): 150 µg/l (95% CI 131-181 µg/l), the day before (n = 51): 105 µg/l (78-131 µg/l), several days ago/non-user (n = 28): 70 µg/l (56-94 µg/l), p < 0.001]. The pattern was similar in the male partners. Apart from a more frequent iodine supplement intake in pregnancy (87.3% vs. partners 15.9%), no systematic differences were observed in urinary measurements between the pregnant women and their partners.

CONCLUSIONS

Time of spot urine sampling and time span from iodine supplement intake to spot urine sampling should be considered when evaluating urinary iodine status in pregnancy.

Augmented renal clearance is a common finding with worse clinical outcome in critically ill patients receiving antimicrobial therapy

INTRODUCTION

We describe incidence and patient factors associated with augmented renal clearance (ARC) in adult intensive care unit (ICU) patients.

MATERIALS AND METHODS

A prospective observational study in a mixed cohort of surgical and medical ICU patients receiving antimicrobial therapy at the Ghent University Hospital, Belgium. Kidney function was assessed by the 24-hour creatinine clearance (Ccr); ARC defined as at least one Ccr of >130 mL/min per 1.73 m2. Multivariate logistic regression analysis: to assess variables associated with ARC occurrence. Therapeutic failure (TF): an impaired clinical response and need for alternate antimicrobial therapy.

RESULTS

Of the 128 patients and 599 studied treatment days, ARC was present in 51.6% of the patients. Twelve percent permanently expressed ARC. ARC patients had a median Ccr of 144 mL/min per 1.73 m2 (IQR 98-196). Median serum creatinine concentration on the first day of ARC was 0.54 mg/dL (IQR 0.48-0.69). Patients with ARC were significantly younger (P<.001). Age and male gender were independently associated with ARC whereas the APACHE II score was not. ARC patients had more TF (18 (27.3%) vs. 8 (12.9%); P=.04).

CONCLUSION

ARC was documented in approximately 52% of a mixed ICU patient population receiving antibiotic treatment with worse clinical outcome. Young age and male gender were independently associated with ARC presence.