A comparative cost-utility analysis of postoperative calcium supplementation strategies used in the current management of hypocalcemia.

BACKGROUND: Symptomatic hypocalcemia is a common complication of total thyroidectomy. Management strategies include responsive treatment initiation for symptoms or prevention by routine or parathyroid hormone-directed calcium supplementation. The comparative cost-effectiveness of even the most often utilized strategies is unclear. METHODS: A Markov cohort model was created to compare routine supplementation with calcium alone (RS), postoperative parathyroid hormone-based selective supplementation with calcium and calcitriol (SS), and no supplementation (NS) in asymptomatic patients. Patients could remain asymptomatic or develop symptomatic hypocalcemia, managed with outpatient oral supplementation or intravenous calcium infusion and administered either inpatient or outpatient. Effectiveness was measured in quality-adjusted life years. Sensitivity analyses were performed to test model parameter assumptions. RESULTS: RS was the preferred strategy, costing $329/patient and resulting in 0.497 quality-adjusted life years, which was only marginally better compared to SS ($373 for 0.495 quality-adjusted life years). NS was most costly at $4,955 for 0.491 quality-adjusted life years. Preference for RS over SS was sensitive to the probability of developing symptoms and the probability of symptom treatment with intravenous supplementation. On probabilistic sensitivity analysis, RS was preferred in 75.4% of scenarios. CONCLUSION: After total thyroidectomy, a preventative calcium supplementation strategy should be strongly considered. In this data-driven theoretical model, RS was the least costly option and resulted in an incremental gain in quality-adjusted life years.

A stochastic estimate of the economic impact of oral calcium supplementation in postparturient dairy cows.

The objective was to develop stochastic models to estimate the economic impact in the first 30 d in milk of oral calcium supplementation to multiparous postparturient dairy cows using 4 different strategies: (1) supplementation of cows with a high previous lactation mature-equivalent milk yield, (2) supplementation of lame cows, (3) supplementation of both cows that have a high previous lactation mature-equivalent milk yield and cows that are lame, and (4) supplementation of all cows. Data from current literature were used to model input variables associated with the costs and risks related to milk production, postparturient disease, and culling. The mean net herd impact per 1,000 calvings for each of the 4 supplementation strategies was $4,425, $5,812, $8,313, and $3,065, respectively. Postpartum supplementation of multiparous lame cows had the highest return on investment at 6.5 to 1, followed by supplementation of multiparous high milk yield and lame cows, multiparous high milk yield cows only, and supplementation of all multiparous postpartum cows with returns of 1.8 to 1, 1.1 to 1, and 0.3 to 1, respectively. A herd's average milk yield at first test had the highest influence on the net impact of oral calcium supplementation to all multiparous cows and accounted for 30% of the variation, followed by the decrease in risk of health events in lame cows given oral calcium at 22%, a herd's prevalence of lameness at calving at 13%, and the price of milk at 10%. Each of the remaining stochastic variables contributed to less than 5% of the variation in net herd financial impact of oral calcium administration. Whereas supplementation of all postpartum multiparous cows returned a positive net herd impact approximately 80% of the time, if a herd was willing to devote time to mature-equivalent milk yield calculations and locomotion scoring, supplementation of this subpopulation of postpartum cows with oral calcium was estimated to have a positive economic impact in all iterations. Depending on the supplementation strategy chosen and baseline milk yield and immediate postpartum lameness prevalence in a herd, a herd with 1,000 calvings per year can expect to see an average net impact ranging from approximately $3,000 to $8,000 after postpartum supplementation of oral calcium in multiparous animals.

Safety, efficacy, and cost savings of single parathyroid hormone measurement for risk stratification after total thyroidectomy.

The management of hypocalcemia (HC) after total thyroidectomy (TTx) is a challenge as TTx is transitioned into a same-day surgery. Measurement of parathyroid hormone (PTH) level after TTx may allow for prediction of postoperative HC and lead to shorter hospital stays. A prospective database was queried between January 2010 and June 2012 with 95 patients who had undergone TTx identified. Patient demographics; preoperative diagnosis; laboratory values and cost; complications; intravenous calcium supplementation; and length of stay (LOS) were analyzed. A PTH-based algorithm was retrospectively applied and theoretical cost savings were analyzed in terms of laboratory cost, LOS, and total cost. Ninety-five patients underwent TTx: 37 patients (38.9%) had cancer, whereas 27 (28.4%) had Graves' disease and the remaining 31 (32.6%) had a benign multinodular goiter. Postoperative PTH was recorded in 72 patients (74.4%); 46 (63.8%) had PTH greater than 10 pg/mL and 26 (36.9%) had PTH less than 10 pg/mL. Transient HC occurred in 10 patients (38.4%) with PTH less than 10 pg/mL (relative risk, 17.69; P = 0.0001). Patients with PTH less than 10 pg/mL incurred a 14.9 per cent higher hospital cost compared with those with PTH greater than 10 pg/mL. With retrospective implementation of the algorithm, there is a potential 46.4 per cent cost savings for the PTH less than 10 pg/mL group, 67.3 per cent savings for the PTH greater than 10 pg/mL group, and 46.7 per cent savings when taken altogether. Algorithmic risk stratification based on postoperative PTH less than 10 pg/mL serves as both a sensitive (100%) and specific (76.7%) predictor of postoperative HC. Such risk stratification may allow for same-day discharge in a number of patients, and even in patients requiring an overnight stay, result in cost savings as a result of a reduction in laboratory expenditures.

Cost savings associated with post-thyroidectomy parathyroid hormone levels.

OBJECTIVES: A 1-hour post-thyroidectomy parathyroid hormone (PTH) level of < or =8 ng/L is predictive of patients who will develop hypocalcemia and guides early supplementation with calcium and vitamin D. However, most hypocalcemic patients fail to meet this criterion. The goal of this study was to determine whether PTH < or = 15 ng/L could be used as a better predictor of hypocalcemia. STUDY DESIGN, SUBJECTS, AND METHODS: This retrospective study involved 270 thyroidectomy patients (2004-2006). PTH and calcium levels, length of admission, supplementation, and rates of hypocalcemia were recorded. RESULTS: Forty-three percent (26/60) of patients developing hypocalcemia met the PTH < or = 8 ng/L cut-off. In contrast, 80% (48/60) of patients developing hypocalcemia had a PTH < or = 15 ng/L. Two point two percent of patients had a 1-hour PTH < or = 15 ng/L and failed to develop hypocalcemia, for a specificity of 97%. CONCLUSIONS: A 1-hour PTH cut-off of < or =15 ng/L for prophylactic supplementation should allow the prevention of the majority of cases of hypocalcemia, leading to significant cost savings by shortening hospital stays.

Clinical and economic impact of falsely decreased calcium values caused by gadoversetamide interference.

OBJECTIVE: Gadolinium is administered as a contrast agent in MRI procedures. Two gadolinium-based contrast agents, gadodiamide and gadoversetamide, interfere with colorimetric total serum calcium methods. The purpose of this prospective observational study was to examine the incidence of calcium interference after gadoversetamide procedures, associated clinical outcomes, and costs 20 months after implementation of quality assurance and physician education programs. MATERIALS AND METHODS: Records of patients who received gadoversetamide from June 24, 2006, to October 7, 2006, were reviewed to determine if a routine calcium test had been performed after the injection. Calcium values were repeated with an alternate method that is less susceptible to gadoversetamide interference. If the difference was > or = 2.0 mg/dL or if the initial test value was < or = 7.0 mg/dL, patient charts were reviewed for any related treatment. Costs associated with this algorithm were tracked. RESULTS: The initial calcium test was performed after gadoversetamide in 766 of 3,439 instances. The alternate test was performed in 633 of 766. One hundred twenty-five of 633 (20%) showed a difference in calcium values that was > or = 0.7 mg/dL, with 16 showing differences of > or = 1.6 mg/dL. Chart review for 56 instances revealed that calcium supplements were administered in 22 of 56 around the time of gadoversetamide injection. However, none appeared to be related to the spurious hypocalcemia. The total additional cost (reagent and technologist) for following this algorithm for just over 3 months was $6,807. CONCLUSION: Approximately 20% of patients receiving gadoversetamide exhibited spurious hypocalcemia. No patients were identified who received inappropriate calcium because of this interference. This may be attributable to the quality assurance and physician education programs.

Benefits resulting from 1- and 6-hour parathyroid hormone and calcium levels after thyroidectomy.

OBJECTIVE: Previous studies have established the efficacy of post-thyroidectomy hypocalcemia monitoring using parathyroid hormone (PTH) and corrected calcium levels at 1 and 6 hours. The goal of this study was to measure the impact of managing patients based on the above findings with respect to: duration of hospital stays, rates of transient hypocalcemia, number of blood tests, cost savings, and discharge from the hospital as early as 8 hours post-thyroidectomy without compromising safety. STUDY DESIGN AND SETTING: This is a prospective study involving 95 total thyroidectomy patients using historical data as controls. The previous protocol was modified in that all blood tests ceased for patients meeting the 6-hour critical level of PTH > or = 28 ng/L and simultaneous corrected calcium > or = 2.14 mmol/L (8.56 mg/dL). Furthermore, patients with 1-hour PTH levels < or = 8 ng/L were prophylactically treated with calcium and vitamin D supplementation. RESULTS: This study demonstrates lower rates of transient hypocalcemia from 28% to 9% (OR = 4.13, P = 0.016), a 10-hour reduction in mean hospital stay, and fewer blood tests (23 vs 15) for patients undergoing total thyroidectomy since the implementation of the new protocol. Furthermore, the experimental protocol resulted in an average cost savings of 766 Canadian dollars per patient. CONCLUSIONS: The new algorithm resulting from PTH and corrected calcium monitoring at 1 and 6 hours post-thyroidectomy has led to significant cost savings for our institution. It has also translated into greater patient satisfaction as a result of fewer blood tests, a lower incidence of transient hypocalcemia, and significantly shorter hospital stays.