Medication Nonadherence and Effectiveness of Preventive Pharmacological Therapy for Kidney Stones.

PURPOSE: Among patients with kidney stones rates of adherence to thiazide diuretics, alkali citrate therapy and allopurinol, collectively referred to as preventive pharmacological therapy, are low. This lack of adherence may reduce the effectiveness of secondary prevention efforts, leading to poorer clinical health outcomes in patients with kidney stones. To examine the impact that medication nonadherence has on the secondary prevention of kidney stones, we compared clinical health outcomes between patients who adhered to their regimen and those who did not. MATERIALS AND METHODS: Using medical and pharmacy claims data we identified adult patients with a physician coded diagnosis for kidney stones. Among the subset with a prescription fill for a preventive pharmacological therapy agent, we then measured adherence to therapy within the first 6 months of initiating treatment using the proportion of days covered formula. We defined adherence as a proportion of days covered value of 80% or greater. Finally, we fitted multivariable logistic regression models to examine the association between medication adherence and the occurrence of a stone related clinical health outcome (an emergency department visit, hospitalization or surgery for stone disease). RESULTS: Of the 8,950 patients who met the study eligibility criteria slightly more than half (51.1%) were adherent to preventive pharmacological therapy. The frequency of emergency department visits, hospitalization and surgery for stone disease was significantly lower among adherent patients. After controlling for sociodemographic factors and the level of comorbid illness, patients who were adherent to therapy had 27% lower odds of an emergency department visit (OR 0.73, 95% CI 0.64-0.84), 41% lower odds of hospital admission (OR 0.59, 95% CI 0.49-0.71) and 23% lower odds of surgery for stone disease (OR 0.77, 95% CI 0.69-0.85) than nonadherent patients. CONCLUSIONS: Our data highlight the consequences of nonadherence to preventive pharmacological therapy among patients with kidney stones. To improve adherence further research is needed to understand patient and provider level factors that contribute to lower rates of adherence.

How Much Information is Lost When You Only Collect One 24-Hour Urine Sample during the Initial Metabolic Evaluation?

PURPOSE: During the initial metabolic evaluation the need for 1 vs 2, 24-hour urine collections is debated. While data suggest that mean urine chemistry measures are similar on consecutive samples, it remains unclear how much, if any, information is lost when only 1 sample is collected. MATERIALS AND METHODS: Using analytical files from Litholink Corporation® (1995 to 2013) we identified adults with kidney stones who underwent initial metabolic testing. Next we determined the subset of patients who collected 2, 24-hour urine samples with urine creatinine varying by 10% or less during a 7-day time window. We then examined the degree of variability in urine chemistry profiles. Specifically we calculated the mean absolute value of the difference between samples as well as the percent difference for individual urine parameters. RESULTS: We identified 70,192 patients meeting our eligibility criteria. While the overall means for individual urine parameters did not vary between samples, the percent difference between the samples varied widely. For example, nearly 1 in 3 patients had a 30% or greater difference in urine calcium and volume between 2 consecutive samples. We noted that inconsistencies between samples often involved multiple parameters. For instance, 29% and 25% of patients had a 20% difference in 2 and 3 or more parameters, respectively. CONCLUSIONS: We observed substantial differences between consecutive 24-hour urine samples that could affect clinical decision making. In light of these findings clinicians must weigh the information lost from only 1 collection vs the burden to the patient of collecting 2.

Provider variation in the quality of metabolic stone management.

PURPOSE: Urinary stone disease is a chronic condition for which secondary prevention (dietary and medical therapy guided by 24-hour urine collection results) has an important role. Assessing the response to these interventions with followup testing is recommended and yet to our knowledge provider compliance with these guidelines is unknown. MATERIALS AND METHODS: Using Litholink® files from 1995 to 2013 we identified adults with urinary stone disease who underwent metabolic evaluation and the providers who ordered the evaluation. By focusing on patients with an abnormality on the initial collection we determined the proportion who underwent a followup test within 6 months of the initial test. Multilevel modeling was done to quantify variation in followup testing among providers after accounting for various patient and provider factors. RESULTS: A total of 208,125 patients had an abnormality on the initial collection, of whom only 33,413 (16.1%) performed a repeat collection within 6 months. While most variation in followup testing was attributable to the patient, the provider contribution was nontrivial (18.0%). The specialty of the ordering provider was important. Patients who saw a urologist had 24% lower odds of repeat testing compared to those who saw a primary care physician (OR 0.76, 95% CI 0.67-0.86, p <0.001). CONCLUSIONS: Followup testing is uncommon in patients with an abnormal initial 24-hour urine collection. Given the observed provider variation, efforts to educate providers on the value of followup testing are likely to have salutary effects on patients with metabolic stone disease.

Factors Associated With Preventive Pharmacological Therapy Adherence Among Patients With Kidney Stones.

OBJECTIVE: To determine adherence patterns for thiazide diuretics, alkali citrate therapy, and allopurinol, collectively referred to as preventive pharmacological therapy (PPT), among patients with kidney stones. METHODS: Using medical claims data, we identified adults diagnosed with kidney stones between 2002 and 2006. Through National Drug Codes, we determined those with one or more prescription fills for a PPT agent. We measured adherence to PPT (as determined by the proportion of days covered formula) within the first 6 months of starting therapy and performed multivariate analysis to evaluate patient factors associated with PPT adherence. RESULTS: Among 7980 adults with kidney stones who were prescribed PPT, less than one third (30.2%) were adherent to their regimen (indicated by proportion of days covered ≥ 80%). Among those on monotherapy, rates of adherence differed by the type of PPT agent prescribed: 42.5% for thiazides, 40.0% for allopurinol, and 13.4% for citrate therapy. Factors that were independently associated with lower odds of PPT adherence included combination therapy receipt, female gender, less generous health insurance, and residence in the South or Northeast. In contrast, older patients and those with salaried employment had a higher probability of PPT adherence. CONCLUSION: Adherence to PPT is low. These findings help providers identify patients where PPT adherence will be problematic. Moreover, they suggest possible targets for quality improvement efforts in the secondary prevention of kidney stones.

Implications of evolving delivery system reforms for prostate cancer care.

OBJECTIVES: Prostate cancer treatment is a significant source of morbidity and healthcare spending. Evolving clinical data have supported expanding surveillance as a means to "right-size" treatment. Integrated delivery systems afford the possibility of hastening this objective. STUDY DESIGN: Retrospective cohort study of Medicare beneficiaries. METHODS: We used a 20% sample of national Medicare claims to assess the impact of healthcare integration on rates of treatment and potential overtreatment in men newly diagnosed with prostate cancer between 2007 and 2011. Rates were measured according to the extent of integration within a market (ie, none, low, intermediate, and high). Generalized estimating equations were used to assess the relationship between integration and utilization, adjusting for confounders. RESULTS: Rates of treatment declined across all markets (P <.01 for overall time trend), but the rate of decline was similar for the 4 market types (P = .27). In the most integrated markets, the rate decreased by 28.8%, or from 55.5 per 10,000 population in 2007 to 39.5 per 10,000 in 2011. After adjusting for confounders, men residing in the most integrated markets were 2.1% less likely to be treated with curative intent compared with those living in areas without integrated delivery systems (P = .04). However, rates of potential overtreatment were similar across all markets regardless of the level of integration (P = .21). CONCLUSIONS: Healthcare integration was associated with small declines in prostate cancer treatment in newly diagnosed men, but not with potential overtreatment. Integrated care alone may be insufficient to curtail potential overtreatment of prostate cancer.

Geographic Variation in the Quality of Secondary Prevention for Nephrolithiasis.

OBJECTIVE: To examine the variation in the quality of secondary prevention for nephrolithiasis across health care markets. METHODS: Using analytical files from Litholink Corporation (2003-2012), we identified adults with nephrolithiasis and abnormal urine biochemistries on 24-hour urine collection. After assigning all patients to a hospital referral region (HRR), we determined the proportion of patients in each HRR who underwent on-treatment follow-up testing (our measure of quality). We then fitted multivariate hierarchical regression models to quantify the amount of variation in this proportion across HRRs. Finally, we examined for associations between a patient's odds of on-treatment follow-up testing and the supply of primary care and specialist physicians in an HRR. RESULTS: The mean rate on-treatment follow-up testing was exceedingly low at only 11.9%. This rate has been stable over time. There was fourfold variation in this rate across HRRs from as little as 6.6% to as high as 23.4%. Those HRRs with higher on-treatment follow-up testing rates tended to have a wealthier and more educated population (P = .01). Receipt of on-treatment follow-up testing was not associated with the number of specialists per capita. CONCLUSION: Wide geographic variation exists in the quality of secondary prevention for patients with nephrolithiasis. Given that current guidelines recommend on-treatment follow-up testing, efforts to increase its uptake are needed.

Statin Use and Risk of Sepsis After Percutaneous Nephrolithotomy.

PURPOSE: To examine the association between statin medication use and sepsis risk after percutaneous nephrolithotomy (PCNL). MATERIALS AND METHODS: Using medical claims data, we identified working-age adults with urinary stone disease who were treated with PCNL. Among this cohort, we determined which patients had a prescription fill for a statin agent that encompassed their surgery date. We then fitted logistic regression models to examine for differences in rates of postoperative sepsis between statin users and nonusers. In addition, we evaluated the frequency of nonfebrile urinary tract infections (UTIs) and intensive care unit (ICU) services utilization and hospital length of stay (LOS) as a function of statin use. RESULTS: During the study period, at total of 2046 patients underwent PCNL, 382 (18.7%) of whom had a prescription fill for a statin agent preceding their surgery. The overall rate of sepsis in this population was 3.8%. After adjusting for patient health status and sociodemographic factors, the rate of postoperative sepsis was comparable between statin users and nonusers (5.3% vs 3.5%, respectively; P=0.105). In addition, UTI and ICU utilization rates did not relate to statin use (P>0.05 for all associations). Adjusted hospital LOS was shorter among statin users, but the difference was clinically trivial (3.6 vs 4.1 days; P=0.007). CONCLUSIONS: Statin use is not associated with reductions in postoperative sepsis, nonfebrile UTIs, ICU utilization, or hospital LOS after PCNL. To increase the safety of PCNL, urologists will have to consider other processes of care (e.g., clinical care pathways).