Severe Hypocalcemia With Denosumab Among Older Female Dialysis-Dependent Patients

Importance

Dialysis-dependent patients experience high rates of morbidity from fractures, yet little evidence is available on optimal treatment strategies. Chronic kidney disease-mineral and bone disorder is nearly universal in dialysis-dependent patients, complicating diagnosis and treatment of skeletal fragility.

Objective

To examine the incidence and comparative risk of severe hypocalcemia with denosumab compared with oral bisphosphonates among dialysis-dependent patients treated for osteoporosis.

Design, Setting, and Participants

Retrospective cohort study of female dialysis-dependent Medicare patients aged 65 years or older who initiated treatment with denosumab or oral bisphosphonates from 2013 to 2020. Clinical performance measures including monthly serum calcium were obtained through linkage to the Consolidated Renal Operations in a Web-Enabled Network database.

Exposures

Denosumab, 60 mg, or oral bisphosphonates.

Main Outcomes and Measures

Severe hypocalcemia was defined as total albumin-corrected serum calcium below 7.5 mg/dL (1.88 mmol/L) or a primary hospital or emergency department hypocalcemia diagnosis (emergent care). Very severe hypocalcemia (serum calcium below 6.5 mg/dL [1.63 mmol/L] or emergent care) was also assessed. Inverse probability of treatment-weighted cumulative incidence, weighted risk differences, and weighted risk ratios were calculated during the first 12 treatment weeks.

Results

In the unweighted cohorts, 607 of 1523 denosumab-treated patients and 23 of 1281 oral bisphosphonate-treated patients developed severe hypocalcemia. The 12-week weighted cumulative incidence of severe hypocalcemia was 41.1% with denosumab vs 2.0% with oral bisphosphonates (weighted risk difference, 39.1% [95% CI, 36.3%-41.9%]; weighted risk ratio, 20.7 [95% CI, 13.2-41.2]). The 12-week weighted cumulative incidence of very severe hypocalcemia was also increased with denosumab (10.9%) vs oral bisphosphonates (0.4%) (weighted risk difference, 10.5% [95% CI, 8.8%-12.0%]; weighted risk ratio, 26.4 [95% CI, 9.7-449.5]).

Conclusions and Relevance

Denosumab was associated with a markedly higher incidence of severe and very severe hypocalcemia in female dialysis-dependent patients aged 65 years or older compared with oral bisphosphonates. Given the complexity of diagnosing the underlying bone pathophysiology in dialysis-dependent patients, the high risk posed by denosumab in this population, and the complex strategies required to monitor and treat severe hypocalcemia, denosumab should be administered after careful patient selection and with plans for frequent monitoring.

Risk of fetal or neonatal death or neonatal intensive care unit admission associated with gadolinium magnetic resonance imaging exposure during pregnancy

BACKGROUND

Concerns have been raised about prenatal exposure to magnetic resonance imaging with gadolinium-based contrast agents because of nonclinical findings of gadolinium retention in fetal tissue and 1 population-based study reporting an association with adverse pregnancy outcomes.

OBJECTIVE

This study aimed to evaluate the association between prenatal magnetic resonance imaging exposure with and without gadolinium-based contrast agents and fetal and neonatal death and neonatal intensive care unit admission.

STUDY DESIGN

We constructed a retrospective cohort of >11 million Medicaid-covered pregnancies between 1999 and 2014 to evaluate the association between prenatal magnetic resonance imaging exposure with and without gadolinium-based contrast agents and fetal and neonatal death (primary endpoint) and neonatal intensive care unit admissions (secondary endpoint). Medicaid claims data were linked to medical records, Florida birth and fetal death records, and the National Death Index to validate the outcomes and gestational age estimates. Pregnancies with multiples, concurrent cancer, teratogenic drug exposure, magnetic resonance imaging focused on fetal or pelvic evaluation, undetermined gadolinium-based contrast agent use, or those preceded by or contemporaneous with congenital anomaly diagnoses were excluded. We adjusted for potential confounders with standardized mortality ratio weighting using propensity scores.

RESULTS

Among 5991 qualifying pregnancies, we found 11 fetal or neonatal deaths in the gadolinium-based contrast agent magnetic resonance imaging group (1.4%) and 73 in the non-gadolinium-based contrast agent magnetic resonance imaging group (1.4%) with an adjusted relative risk of 0.73 (95% confidence interval, 0.34-1.55); the neonatal intensive care unit admission adjusted relative risk was 1.03 (0.76-1.39). Sensitivity analyses investigating the timing of magnetic resonance imaging or repeat magnetic resonance imaging exposure during pregnancy and simulating the impact of exposure misclassification corroborated these results.

CONCLUSION

This study addressed the safety concerns related to prenatal exposure to gadolinium-based contrast agents used in magnetic resonance imaging and the risk thereof on fetal and neonatal death or the need for neonatal intensive care unit admission. Although the results on fatal or severe acute effects are reassuring, the impact on subacute outcomes was not evaluated.

Idelalisib for Treatment of Relapsed Follicular Lymphoma and Chronic Lymphocytic Leukemia: A Comparison of Treatment Outcomes in Clinical Trial Participants vs Medicare Beneficiaries

Importance

Idelalisib (IDEL) is approved as monotherapy in relapsed follicular lymphoma (FL) and with rituximab (IDEL+R) for relapsed chronic lymphocytic leukemia (CLL). Toxic effects can be severe and treatment-limiting. Outcomes in a real-world population are not yet characterized.

Objective

We compared IDEL treatment outcomes in the clinical setting with outcomes in clinical trial data.

Design, Setting, and Participants

This cohort study compared clinical trial participants treated with IDEL, aged 65 years or older, in studies 101-09 and 312-0116 with Medicare beneficiaries treated with IDEL of the same disease state and treatment regimen. Study 101-09 was a phase 2, single-group, open-label trial supporting accelerated approval of IDEL for relapsed or refractory FL. Study 312-0116 was a phase 3, multicenter, randomized, double-blind trial supporting approval of IDEL+R for relapsed CLL. Analyses were conducted between February and December 2018.

Main Outcomes and Measures

Treatment duration, on-treatment and overall mortality, and serious and fatal infections were compared between trial participants and Medicare beneficiaries. Cox proportional hazards models quantified differences by cohort.

Results

We identified 26 trial participants (mean [SD] age, 73 [4.9] years; 12 [46.2%] women) and 305 Medicare beneficiaries (mean [SD] age, 76 [6.9] years; 103 [54.8%] women) receiving IDEL for FL and 89 trial participants (mean [SD] age, 74 [6.0] years; 30 [33.7%] women) and 294 Medicare beneficiaries (mean age, 76 [6.3] years; 111 [37.8%] women) receiving IDEL+R for CLL. Medicare beneficiaries were older with higher comorbidity; had a shorter median treatment duration for CLL (173 days vs 473 days, P < .001) but not FL (114, days vs 160 days, P = .38); a numerically higher mortality rate (CLL: HR, 1.40; 95% CI, 0.93-2.11; FL: HR, 1.39; 95% CI, 0.69-2.78); and a significantly higher fatal infection rate per 100 person-years for CLL (18.4 vs 9.8, P = .04) and a numerically higher rate for FL (27.6 vs 18.6, P = .54), compared with trial participants. Trial participants had approximately twice as many dose reductions (CLL: 32.6% vs 18.0%; P = .003; FL: 38.5% vs 16.1%; P = .02). Among Medicare beneficiaries, a hospitalized infection within 6 months prior to IDEL initiation was associated with a 2.11-fold increased risk for on-treatment fatal infections (95% CI, 1.44-3.10). Despite a March 2016 recommendation for Pneumocystis jirovecii pneumonia prophylaxis in patients treated with IDEL, prophylaxis rates were low after March 2016 (FL: 25%, CLL: 37%).

Conclusions and Relevance

We observed substantial imbalances in baseline comorbidities and treatment outcomes between Medicare beneficiaries and trial participants aged 65 years or older. Immunosuppression-related toxic effects, including infections, may have been somewhat reduced in trials by more frequent dose reductions and exclusion of patients with ongoing infections. Selective eligibility criteria and closer monitoring of trial patients may be responsible for limited generalizability of trial data to clinical practice.

First-Trimester Exposure to Gadolinium-based Contrast Agents: A Utilization Study of 4.6 Million U.S. Pregnancies

BackgroundThe safety of gadolinium-based contrast agent (GBCA) exposure during pregnancy has not been established, and the use of GBCAs during pregnancy is not recommended unless it is essential to the health of the woman or fetus.PurposeTo examine the prevalence of GBCA exposure in a large sample of pregnancies resulting in a live birth.Materials and MethodsThe Sentinel Distributed Database was used to retrospectively identify U.S. pregnancies that resulted in live births between 2006 and 2017 from 16 data partners. The main outcome was the prevalence of MRI procedures with and without GBCAs, sorted by anatomic location and trimester, among pregnant and matched comparator women.ResultsAmong 4 692 744 pregnancies resulting in a live birth, we identified 6879 exposures to GBCAs in 5457 pregnancies, representing one contrast-enhanced MRI examination per 860 pregnancies (0.12% of all pregnancies). Most contrast-enhanced MRI examinations were performed in the head (n = 3499), although pelvic and abdominal MRI constituted 22.3% (n = 1536) of all contrast-enhanced MRI examinations during pregnancy. The majority (70.2%) of GBCA exposures occurred during the first trimester, with a 4.3-fold greater prevalence compared with that in the second trimester and a 5.1-fold greater prevalence compared with that in the third trimester.ConclusionThis study identified higher rates of gadolinium-based contrast agent (GBCA) exposure during the first few weeks of pregnancy compared with the later weeks of pregnancy, suggesting inadvertent exposure to GBCAs might occur before pregnancy is recognized.© RSNA, 2019Online supplemental material is available for this article.See also the editorial by Kallmes and Watson in this issue.

Misclassification in Assessment of First Trimester In-utero Exposure to Drugs Used Proximally to Conception: the Example of Letrozole Utilization for Infertility Treatment

Letrozole is an aromatase inhibitor that has an unapproved use for ovulation induction with infertility. Because of the proximity of this use to conception, we selected letrozole to study the effect of 3 different methods for identifying the pregnancy start date and their impact on exposure misclassification. Using electronic health data from the US Sentinel database (2001-2015), we identified live-birth pregnancies conceived through in-vitro fertilization or intrauterine insemination. The pregnancy start was calculated using 1) a validated algorithm to estimate the last menstrual period (LMP), 2) LMP + 14 days (i.e., conception estimate), and 3) the fertility-procedure date. We identified 47,628 live-births after intrauterine insemination (n = 24,962) and in-vitro fertilization (n = 22,666), in which 2,458 (5.3%) mothers received letrozole. The algorithm-based conception estimate occurred within 14 days of the fertility procedure for 78.3% of pregnancies. Defining pregnancy start as LMP (45.7/1,000 pregnancies) or LMP + 14 days (12.7/1,000 pregnancies) overestimated letrozole exposure during pregnancy by 8.4-fold and 2.3-fold, respectively, compared with defining it at the date of the fertility procedure (5.5/1,000 pregnancies). While most studies of drug utilization in pregnancy use LMP as the conventional pregnancy start, this introduced substantial exposure misclassification in the example of letrozole. LMP + 14 days was less biased. Researchers should carefully consider the impact of the method for identifying the pregnancy start date on the potential for exposure misclassification.

A systematic review of pregnancy exposure registries: examination of protocol-specified pregnancy outcomes, target sample size, and comparator selection

PURPOSE

Our study sought to systematically evaluate protocol-specified study methodology in prospective pregnancy exposure registries including pre-specified pregnancy outcomes, power calculations for sample size, and comparator group selection.

METHODS

U.S. pregnancy exposure registries designed to evaluate safety of drugs or biologics were identified from www.clinicaltrials.gov, the FDA's Office of Women's Health website, and the FDA's list of postmarketing studies. Protocols or similar documentation were obtained.

RESULTS

We identified 35 U.S. registries for drugs or biologic use during pregnancy. All registries assessed risk for overall major congenital malformations. Pre-specified target enrollment was stated for 18 (51%) registries, and ranged from 150 to 500 exposed pregnancies (median 300). Thirty-two (91%) registries identified at least one comparison group, but only nine (26%) planned to use an internal comparator. The most common external comparator group (n = 24, 69%) was the Metropolitan Atlanta Congenital Defects Program (MACDP).

CONCLUSIONS

No registries were designed to have sufficient power to assess specific malformations, despite the plausibility that most teratogens cause specific defects. Only half of the registries included a power analysis. Despite their common use, external comparators, including MACDP, have important limitations. In the absence of randomized controlled trial data in pregnant women, pregnancy registries remain an important tool as part of a comprehensive pregnancy surveillance program; however, pregnancy registries alone may not be sufficient to obtain adequate data regarding risks of specific malformations. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Cardiovascular and mortality risk in elderly Medicare beneficiaries treated with olmesartan versus other angiotensin receptor blockers

PURPOSE

In the randomized trial, Randomized Olmesartan and Diabetes Microalbuminuria Prevention, acute cardiovascular death was increased nearly fivefold in diabetic patients treated with high-dose olmesartan, an angiotensin receptor blocker (ARB), compared with placebo.

METHODS

Medicare beneficiaries were entered into new-user cohorts of olmesartan or other ARBs and followed on therapy for occurrence of acute myocardial infarction, stroke, or death. Analyses focused on specific subgroups defined by diabetes status, ARB dose, and duration of therapy. Hazard ratios (HR) with 95% confidence intervals (CIs) were estimated using Cox proportional hazards regression, with other ARBs as reference.

RESULTS

A total of 158,054 olmesartan and 724,673 other ARB users were followed for 54,285 and 260,390 person-years, respectively, during which 9237 endpoint events occurred. Lower-dose olmesartan was not associated with increased risk for any endpoint, regardless of duration of use. High-dose olmesartan for 6 months or longer was associated with increased risk of death in patients with diabetes (HR 2.03, 95%CI 1.09-3.75, p = 0.02) and with reduced risk in nondiabetic patients (HR 0.46, 95%CI 0.24-0.86, p = 0.01). Some, but not all, sensitivity analyses suggested that selective prescribing of olmesartan to healthier patients (channeling bias) may have accounted for the reduced risk in nondiabetic patients.

CONCLUSIONS

High-dose olmesartan was associated with an increased risk of death in diabetic patients treated for 6 months or longer and with a reduced risk of death in nondiabetic patients, when compared with use of other ARBs. This latter effect was probably because of selective prescribing of olmesartan to healthier patients, although effect modification cannot be excluded. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Hallucinations and other psychotic symptoms associated with the use of attention-deficit/hyperactivity disorder drugs in children

OBJECTIVES

To gain a better understanding of the capacity of psychostimulant medications to induce adverse psychiatric reactions and determine the frequency of such reactions, we analyzed postmarketing surveillance data and clinical trial data for drugs, either approved or under development, for the treatment of attention-deficit/hyperactivity disorder.

METHODS

The US Food and Drug Administration requested manufacturers of drugs approved for attention-deficit/hyperactivity disorder or with active clinical development programs for that indication to search their electronic clinical trial databases for cases of psychosis or mania using prespecified search terms. The manufacturers supplied descriptions of clinical trials, numbers of patients exposed to study drug, and duration of exposure to permit calculations of incidence rates. Independently, cases of psychosis or mania in children and adults for drugs used to treat attention-deficit/hyperactivity disorder from the Food and Drug Administration Adverse Event Reporting System safety database were analyzed. Manufacturers were asked to conduct similar analyses of their postmarketing surveillance databases.

RESULTS

We analyzed data from 49 randomized, controlled clinical trials in the pediatric development programs for these products. A total of 11 psychosis/mania adverse events occurred during 743 person-years of double-blind treatment with these drugs, and no comparable adverse events occurred in a total of 420 person-years of placebo exposure in the same trials. The rate per 100 person-years in the pooled active drug group was 1.48. The analysis of spontaneous postmarketing reports yielded >800 reports of adverse events related to psychosis or mania. In approximately 90% of the cases, there was no reported history of a similar psychiatric condition. Hallucinations involving visual and/or tactile sensations of insects, snakes, or worms were common in cases in children.

CONCLUSIONS

Patients and physicians should be aware that psychosis or mania arising during drug treatment of attention-deficit/hyperactivity disorder may represent adverse drug reactions.

The hemodynamic effects of long-term ACE inhibition with fosinopril in patients with heart failure. Fosinopril Hemodynamics Study Group

The objective of this study was to evaluate the hemodynamic and clinical effects of fosinopril in patients with heart failure. This was a prospective, multicenter, double-blind, randomized, parallel-group study. Patients 18 to 80 years of age who were receiving diuretics with a systolic blood pressure (SBP) > or = 90 mm Hg, New York Heart Association (NYHA) functional class II-IV, left ventricular ejection fraction < or = 40%, pulmonary capillary wedge pressure (PCWP) > or = 18 mm Hg, and a cardiac index (CI) < or = 2.6 L/min/m(2) were eligible. A total of 179 patients were randomized to a single, double-blind oral dose of placebo or fosinopril at 1, 20, or 40 mg, and hemodynamic monitoring was performed for 24 hours postdose; 155 patients with SBP > or = 90 mm Hg were re-randomized to 10 weeks of double-blind fosinopril at 1, 20, or 40 mg once daily. Hemodynamic monitoring was repeated at the last visit, beginning at 24 hours postdose (trough) and continuing for 12 hours thereafter. Significant decreases in preload (PCWP) and afterload (mean arterial blood pressure [MABP] and systemic vascular resistance [SVR]) were evident 3 to 4 hours after a single dose of fosinopril at 20 and 40 mg and continuing for up to 8 to 12 hours postdose for PCWP and SVR and for up to 24 hours postdose for MABP (P < or = .05 v placebo and baseline). Sustained decreases in PCWP, MABP, SVR, and heart rate and increases in CI and stroke volume index were observed after 10 weeks of treatment with fosinopril at 20 and 40 mg once daily (P < or = .05 v 1 mg group for PCWP and MABP at most time points and P < or = .05 v baseline for other parameters at most time points). Dose-related trends toward reduced supplemental diuretic use (P = .027) and reduced symptoms of dyspnea (P = .008) were observed with the 20-mg and 40-mg fosinopril dose groups. Once daily administration of fosinopril at 20 and 40 mg was safe and well tolerated, provided a sustained beneficial hemodynamic effect, improved left ventricular performance, and reduced symptoms of dyspnea, resulting in a reduced need for supplemental diuretic therapy.

Effects of fosinopril on exercise tolerance, symptoms, and clinical outcomes in patients with decompensated heart failure

The purpose of this prospective, multicenter, randomized, double blind, placebo controlled study was to determine the clinical effects of fosinopril in patients with decompensated or worsening heart failure (HF). Patients >/=18 years with New York Heart Association (NYHA) functional class II-IV HF who had been hospitalized or seen in the ER or outpatient clinic for treatment of worsening or decompensated HF were eligible. Patients had to be on diuretic therapy and have a left ventricular ejection fraction (LVEF) </=35% and a treadmill exercise tolerance test (ETT) duration of </=8 minutes. Randomized patients began 12 weeks of fosinopril 10 mg (or placebo) qAM and were titrated within 4 weeks to fosinopril 20 mg and then to 40 mg (or placebo) qAM (if seated, systolic blood pressure (SBP) >/=90 mm Hg). ETTs (modified Naughton protocol) were performed at weeks 1, 3, 6, and 12. A total of 206 patients (mean age 62 years) were randomized to fosinopril (n=102) or placebo (n=104). Most patients were NYHA functional class III (58%) or IV (30%) at presentation; 145 patients completed 12 weeks of treatment (fosinopril, n=85; placebo, n=60). After adjustment for baseline imbalances and investigator effects, fosinopril-treated patients had a 513 second mean exercise duration at endpoint vs. a 489 second duration in placebo-treated patients (p=0.353). When the analysis was adjusted for the impact of dropouts on ETT time, fosinopril-treated patients had a greater exercise duration than those treated with placebo (p=0.043). Fewer patients in the fosinopril group were discontinued from study medication (p=0.008) or hospitalized (p=0.005) for worsening HF. At endpoint, more patients improved their NYHA Functional Class and fewer had worsened with fosinopril vs. placebo (p=0.018); fosinopril-treated patients showed improvements in dyspnea (p=0.054), fatigue (p=0.052), edema (p=0.012), and paroxysmal nocturnal dyspnea (p=0.003) vs. the placebo group. Once-daily fosinopril had a favorable effect on dropout-adjusted exercise tolerance, reduced the frequency of discontinuations or hospitalizations for worsening HF, improved HF signs and symptoms, and was safe and well tolerated. (c)1999 by CHF, Inc.

Fosinopril attenuates clinical deterioration and improves exercise tolerance in patients with heart failure. Fosinopril Efficacy/Safety Trial (FEST) Study Group

This study was a 12-week, double-blind, placebo-controlled, multinational trial of fosinopril in 308 patients with mild to moderately severe heart failure (New York Heart Association [NYHA] functional class IIS 17%, IIM 48%, and III 35%; mean ejection fraction [+/-SD] 26.5% [+/-6.9%]; bicycle exercise duration 1 to 11 min). An initial dose of 10 mg once daily was titrated as tolerated to 40 mg once daily. Patients all received diuretic therapy; digoxin was optional. The primary endpoint was maximal bicycle exercise time; a secondary endpoint was occurrence of the following prospectively defined, ordered clinical events indicative of worsening heart failure: death, study discontinuation, hospitalization, emergency room visits, and need for supplemental diuretic. At study endpoint (last value obtained for each patient), bicycle exercise time increased more with fosinopril (38.1 s) than with placebo (23.5 s) (P = 0.101 by ANCOVA and 0.010 by prospectively defined dropout-adjusted endpoint analysis). More patients remained free of clinical events indicative of worsening heart failure when treated with fosinopril (89%) than with placebo (75%), and the worst events of fosinopril-treated patients tended to be less severe than those of placebo patients (P = 0.001). Analysis of the occurrence of individual clinical events showed that the need for supplemental diuretic was markedly reduced with fosinopril (8% vs 20%, of patients, P = 0.002), as were hospitalizations (3% vs 12% of patients, P = 0.002) and study discontinuations (2% vs 12% of patients, P < 0.001) for worsening heart failure; the two groups had similar incidences of death (3% of patients in the fosinopril group vs 2% in the placebo group, P = 0.723). In addition, symptoms of dyspnoea (P = 0.017), fatigue (P = 0.019), and NYHA functional class (P = 0.008) improved with fosinopril relative to placebo. In conclusion, fosinopril, at an initial dose of 10 mg once daily, subsequently titrated as tolerated to 40 mg once daily, increased exercise tolerance and reduced the frequency of clinical events indicative of worsening heart failure.

Effects of fosinopril on exercise tolerance and clinical deterioration in patients with chronic congestive heart failure not taking digitalis. Fosinopril Heart Failure Study Group

A total of 241 men and women with mild to moderately severe chronic heart failure (New York Heart Association functional class II [90%] or III) and a mean (+/- SD) left ventricular ejection fraction of 25 +/- 7%, entered a 24-week, prospective, double-blind, placebo-controlled trial of 10 or 20 mg/day of fosinopril, a phosphinic acid angiotensin-converting enzyme inhibitor. Patients received concomitant diuretic therapy but not digitalis. Primary end points were mean change in maximal treadmill exercise time and occurrence of prospectively defined clinical events indicative of worsening heart failure (most to least severe): death, withdrawal for worsening heart failure, hospitalization for worsening heart failure, need for supplemental diuretic or emergency room visit for worsening heart failure, and no event. At study end point, treadmill exercise time had improved in the fosinopril versus the placebo group (+28.4 vs -13.5 seconds, p = 0.047). New York Heart Association functional class had improved at end point more frequently (24% vs 13%) and deteriorated less frequently (18% vs 32%) in the fosinopril group (p = 0.003). More patients treated with fosinopril (66% vs 50%) remained free of clinical events indicative of worsening heart failure, and fosinopril-treated patients had less severe clinical events (p = 0.004). Dyspnea, fatigue, and paroxysmal nocturnal dyspnea improved more often and worsened less often in this group (p < or = 0.002), and edema showed a trend toward improvement (p = 0.088). These clinical benefits did not require concomitant digitalis therapy. Fosinopril was associated with an acceptable safety profile.

Acute occupational respiratory diseases in hospital discharge data

We investigated the feasibility of using hospital discharge diagnoses of ICD codes 506, 507, and 508, respiratory diseases from external sources, to identify occupational sentinel health events [SHE(O)]. Two hundred sixty-nine records were reviewed and 66 (25%) were incidents where the work-relatedness of the respiratory diseases was documented in the medical records. Twenty-six percent of the 269 records contained no exposure information. Sixty-four of the 66 occupational cases were from ICD codes 506.0-506.9, with the largest number classified as ICD codes 506.0 (bronchitis and pneumonitis due to fumes and vapors) and 506.3 (other acute and subacute respiratory conditions due to fumes and vapors). We conclude that surveillance of ICD codes in the 506 series, where 39% of the cases were secondary to occupational exposures, is a valuable component of a surveillance system for preventable occupational lung disease.