Kurt, Anita, PhD, RN

Quiñones, Joanne, MD, MSCE

Rochon, Meredith, MD

Smulian, John C, MD, MPH

Tun, Christina, MD

English

Lehigh Valley Health Network: LVHN Scholarly Works

Lehigh Valley Health NetworkLVHN Scholarly WorksDepartment of Obstetrics & GynecologyComparison of 12-hour Urine and Protein:Creatinine Ratio to 24-hour Urine for theDiagnosis of Preeclampsia (Poster)Christina Tun MDLehigh Valley Health NetworkJoanne Quiñones MD, MSCELehigh Valley Health Network, Joanne_N.Quinones@lvhn.orgAnita Kurt PhD, RNLehigh Valley Health Network, Anita.Kurt@lvhn.orgJohn C. Smulian MD, MPHLehigh Valley Health Network, john.smulian@lvhn.orgMeredith Rochon MDLehigh Valley Health Network, Meredith_L.Rochon@lvhn.orgFollow this and additional works at: http://scholarlyworks.lvhn.org/obstetrics-gynecologyPart of the Diseases Commons, Maternal, Child Health and Neonatal Nursing Commons, andthe Obstetrics and Gynecology CommonsThis Poster is brought to you for free and open access by LVHN Scholarly Works. It has been accepted for inclusion in LVHN Scholarly Works by anauthorized administrator. For more information, please contact LibraryServices@lvhn.org.Published In/Presented AtTun, C., Quinones, J., Kurt, A., Smulian, J., & Rochon, M. (2012, February). Comparison of 12-hour Urine and Protein: Creatinine Ratioto 24-hour Urine for the Diagnosis of Preeclampsia. Presented at: The Society for Maternal Fetal Medicine Meeting, Dallas, TX.1Obstetrics and Gynecology, Lehigh Valley Health Network, Allentown, PennsylvaniaComparison of 12-hour Urine and Protein:Creatinine Ratio to 24-hour Urinefor the Diagnosis of PreeclampsiaChristina Tun, MD1; Joanne Quiñones, MD, MSCE1; Anita Kurt, PhD1; John Smulian, MD, MPH1; Meredith Rochon, MD1Abstract OBJECTIVE:  The standard threshold value of proteinuria in the setting of hypertension for the diagnosis of preeclampsia is a 24-hour urine protein (24-hr) ≥ 300mg. Equivalent values have been generated for more convenient and/or cost-effective tests, such as the 12-hour urine protein (12-hr) and protein:creatinine ratio (PCR), but these have not been tested prospectively. The purpose was to compare the performance of the 12-hr and PCR to a standard 24-hr ≥ 300mg for the diagnosis of preeclampsia.  STUDY DESIGN:  This was a prospective observational study of women admitted to the Lehigh Valley Health Network from 7/1/2010 to 12/31/2011 for diagnosis and/or management of preeclampsia. For each patient, PCR, 12-hr and 24-hr urine specimens were collected. Only the 24-hr result was used for clinical management. Test characteristics for identifying 24-hr ≥ 300mg were calculated. Cutoff values were based on previously published data. RESULTS:  A total of 102 patients were enrolled during the study period, 12 of which were subsequently excluded (11 delivered prior to completion, 1 was excluded due to lab error) for a final cohort of 90 patients. Twenty-eight (31%) of the final cohort had 24-hr ≥ 300mg. Both 12-hr > 165mg and PCR > 0.15 correlate significantly with 24-hr ≥ 300mg (r=0.99, p<0.001 and r=0.54, p<0.001, respectively). Test characteristics for 12-hr > 165mg and PCR > 0.15 are shown in Table 3. CONCLUSION:  12-hr > 165mg performed well as a predictor of 24-hr ≥ 300mg, with the benefit of a shorter evaluation time. The high negative predictive value of PCR suggests that it may be most useful in identifying patients that do not have 24-hr ≥ 300mg. Use of both these tests can be considered in the evaluation and management of patients with suspected preeclampsia. BackgroundProtein excretion is variable in the setting of preeclampsia, therefore it is recommended that a 24-hour urine be used for the diagnosis (1-3). Other tests for the diagnosis of preeclampsia have been proposed, including 12-hour urine protein > 165mg and/or protein:creatinine ratio (PCR) > 0.15 (4-7), but have not been prospectively tested.  Conclusions •  12-hr urine protein > 165mg is a good surrogate for 24-hr urine protein ≥ 300mg with the potential benefit of earlier diagnosis and treatment of preeclampsia•  Protein:creatinine ratio > 0.15 may be most useful as a screening tool to rule out 24-hr urine protein ≥ 300mg due to its high negative predictive value•  Applying these results to the management of patients with suspected preeclampsia has the potential to:   -  Improve compliance with outpatient collection   -  Decrease healthcare costs by decreasing the number of admissions and length of admissions   -  Decrease morbidity by decreasing time to diagnosisReferences1.  Report of the National High Blood Pressure Education Program Working Group on High Blood Pressure in Pregnancy.  Am J Obstet Gynecol 2000;183:S1-S22.2.  Cunningham FG, Leveno KJ, Bloom SL, Hauth JC, Rouse D, Spong C. Pregnancy Hypertension. In: Williams Obstetrics. 23nd ed. New York: McGraw-Hill, 2010: Chapter 34.3.  Diagnosis and Management of Preeclampsia and Eclampsia. ACOG Practice Bulletin No.33. American College of Obstetricians and Gynecologists. 2002 4.  Lindheimer M, Kanter, D. Interpreting abnormal proteinuria in pregnancy: the need for a more pathophysiological approach. Obstet Gynecol 2010 Feb; 115(2 Pt 1):365-75.5.  Rinehart BK, Terrone DA, Larmon JE, Perry KG Jr, Martin RW, Martin JN Jr. A 12-hour urine collection accurately assesses proteinuria in the hospitalized hypertensive gravida. J Perinatol 1999;19:556-8.6.  Adelberg AM, Miller J, Doerzbacher M, Lambers DS. Correlation of quantitative protein measurements in 8-, 12-, and 24-hour urine samples for the diagnosis of preeclampsia. Am J Obstet Gynecol 2001,185:804-807.7.  Schubert FP, Abernathy MP. Alternative evaluations of proteinuria in the gravid hypertensive patient. J Reprod Med 2006;51:709-714Methods •  Inclusion criteria: All pregnant women > 20 weeks’ gestation admitted to the Lehigh Valley Health Network antepartum unit undergoing a 24-hour urine protein for diagnosis and/or management of preeclampsia from 7/1/2010 – 12/31/2011.   •  Exclusion criteria: Prepregnancy renal disease (defined as 24-hr urine protein ≥ 300mg), clinical indication for delivery at the time of admission, age<18 or >55, non-english speaking or previous enrollment in the study.    •  Primary outcome: test performance of 12-hr urine protein and PCR to predict 24-hr urine protein ≥ 300mg.  •  PCR, 12-hr urine protein, and 24-hr urine protein were collected on each subject. Providers were blinded to the 12-hr and PCR results. Care was otherwise routine. Urine collection was initiated at the time of admission. Subjects were on modified bedrest.•  Data were analyzed using STATA 9.2 statistical software. A p-value of < 0.05 was considered statistically significant. •  IRB approved.  Objective To determine the performance of 12-hr urine protein > 165mg and PCR > 0.15 for predicting 24-hr urine protein ≥ 300mg. Results Future Studies •  Develop and prospectively study a clinical algorithm for the diagnosis of preeclampsia incorporating 12-hr urine protein and protein:creatinine ratio in both the inpatient and outpatient settings• Correlate these test cutoffs with maternal and fetal outcomesWeaknesses •  Small sample size lacks power to correlate with maternal and fetal outcomes•  May not be generalizable to outpatient setting – uncertain impact of hospitalization (diet, sleep pattern, activity)Strengths •  “Real life” study design generalizable to clinical practice• First study to prospectively test previously generated cutoffs•  Inpatient setting allowed consistency and compliance with collection technique102 E nro lled12 E xc luded11 de livered <24 hrs1 lab error6224-hr p ro te in < 300 m g2824-hr p ro te in > 300 m g58 12-hr urine59 P C R28 12-hr urine27 P C RFigure 2: 12-hour urine protein vs. 24-hour urine protein Figure 3: ROC for 12-hour urine proteinFigure 4: Protein:creatinine ratio vs. 24-hour urine protein Figure 5: ROC for protein:creatinine ratio0PCR024hrProt2000400060001 2 3 4 5 0 .001 - Specificity0 .00SensitivityArea under ROC curve = 0.87700 .25 0 .50 0 .75 1 .000 .250 .500 .751 .000 500 1000 1500 2000 250012hr Prot020004000600024hrProt0 .001 - Specificity0 .00Sensitivity0 .25 0 .50 0 .75 1 .000 .250 .500 .751 .00Area under ROC curve = 0.9975Table 3. Test characteristics of 12-hr urine protein > 165 mg and protein: creatinine ratio > 0.15 for the prediction of 24-hr urine protein ≥ 300 mg           12-hr urine protein >165mg PCR > 0.15Sensitivity 96 (90-99) 89 (81-94)Specificity 100 (96-100)* 49 (39-59)PPV 100 (96-100)* 32 (23-42)NPV 98 (93-100) 91 (84-96)Data are in % (95% confidence interval). PCR, protein:creatinine ratio. PPV, positive predictive value. NPV, negative predictive value.*Confidence interval is 97.5%. Table 2. Urine collection characteristics by 24 hour urine protein result           24-hr protein < 300 mg(N=62)24-hr protein ≥ 300 mg(n=28)P-value24-hr urine protein (mg) 175 (90-290) 520 (310-6360) <0.00124-hr urine volume (ml) 2300 (700-4700) 1825 (600-5100) 0.2324-hr urine CrCl (ml/min) 153 (59-272) 135 (80-283) 0.5112-hr urine protein (mg) 70 (40-150) 255 (120-2640) <0.00112-hr urine volume (ml) 1050 (40-2300) 1050 (300-3050) 0.9712-hr urine protein > 165mg 0 (0%) 27 (96%) <0.001Protein:creatinine ratio 0.16 (0.07-0.5) 0.35 (0.14-4.57) <0.001Protein:creatinine ratio > 0.15 30 (52%) 24 (89%) 0.001Data are in median (range) or n (%). CrCl, creatinine clearance. Table 1. Baseline maternal characteristics by 24 hour urine protein result           24-hr protein < 300 mg(N=62)24-hr protein ≥ 300 mg(n=28)P-valueMaternal age (yrs) 29 (19-42) 30 (19-38) 0.76Race/Ethnicity    Caucasian    Black    Asian    Hispanic49 (79%)2 (3%)3 (5%)1 (2%022 (79%)3 (11%)0 (0%)1 (4%)0.41Private insurance 45 (73%) 20 (71%) 0.91Multiparous 29 (47%) 20 (71%) 0.03Multiple gestation 8 (13%) 3 (11%) 0.77BMI 33.1 (19.5-69.9) 36.4 (25.4-54.9) 0.13Gestational age (wks) 34.3 (29.9-39.0) 32.8 (24.0-35.4) 0.007Smoking 13 (21%) 4 (14%) 0.45Comorbidity (any)*    cHTN    gHTN or preeclampsia    Pregestational diabetes    Gestational diabetes57 (91%)12 (19%)15 (24%)1 (2%)9 (13%)26 (93%)8 (29%)7 (25%)1 (2%)4 (14%)0.880.330.930.0150.30Indications for admission*    Elevated blood pressure    Proteinuria    Symptoms^    Lab abnormalities    Fetal growth restriction    Other+51 (82%)16 (26%)28 (45%)7 (11%)10 (16%)9 (15%)26 (93%)19 (68%)14 (50%)11 (39%)3 (14%)6 (21%)0.19<0.0010.670.0020.500.42Median SBP during collection 131 (99-165) 136 (105-152) 0.11Median DBP during collection 76 (53-98) 78 (55-99) 0.41Data are in median (range) or n (%). BMI, body mass index. *Subject may have more than one. cHTN, chronic hypertension. gHTN, gestational hypertension. ^Includes headache, scotomata, abdominal pain, and significant weight gain associated with edema. +Includes shortness of breath, seizure of uncertain origin, oligohydramnios, visual changes other than scotomata. SBP, systolic blood pressure. DBP, diastolic blood pressure. r=0.99p<0.001 r=0.54p<0.001 Figure 1: Summary of Patient Enrollment** Due to collection or lab error, some patients did not have results for both 12-hr urine and PCR

Comparison of 12-hour Urine and Protein: Creatinine Ratio to 24-hour Urine for the Diagnosis of Preeclampsia (Poster)

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Comparison of 12-hour Urine and Protein: Creatinine Ratio to 24-hour Urine for the Diagnosis of Preeclampsia (Poster)

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