Consecutive 6-month Periods Research Articles

Systematic use of carbetocin during cesarean delivery of multiple pregnancies: a before-and-after study

Cesarean deliveries of multiple pregnancies are associated with a high risk of hemorrhage. The aim of this study is to evaluate the efficacy of carbetocin administered systematically during cesarean deliveries of multiple pregnancies. Single-center retrospective before-and-after study comparing the use of carbetocin to that of oxytocin during cesareans during two consecutive 6-month periods. A composite variable was predefined as the principal endpoint: any one or more of bleeding ≥1,500mL, transfusion, hemoglobin reduction of 4g/dL or more or operative intervention (surgery, embolization). In an intention-to-treat analysis, the comparison of the two groups (n=24 before and n=39 after) showed no difference for the occurrence of the composite variable (16.7 vs. 15.4%, p=0.89). Nor did the per-protocol analysis (n=24 before and n=27 after) differ for it (16.7 vs. 14.8%, p=0.86). Moreover, none of the secondary outcome measures studied-moderate blood loss, prescription of sulprostone, cell-saver use, and intravenous iron infusion-differed significantly between the two periods. In our population of multiple pregnancies delivered by cesarean, carbetocin did not appear more effective than oxytocin in preventing severe postpartum hemorrhage.

An affordable proxy of representative national survey on radon concentration in dwellings: Design, organisation and preliminary evaluation of representativeness

Representative national surveys in dwellings are important to unbiasedly evaluate the exposure of the general population to radon. In Italy, a representative national survey was conducted from 1989 to 1996, which involved about 5600 dwellings in 232 towns. Later on, some Regions carried out more detailed surveys, but a new national survey in dwellings is necessary in order to obtain a more thorough estimate of radon concentration distribution over the Italian territory. The need to make this survey in an affordable way led to implement a new approach based on the collaboration between the Istituto Superiore di Sanità and a national company with workplaces and employees' homes throughout the country. The intent is to carry out a proxy of a population representative survey by measuring radon concentration in the homes of a random sample of the company employees. The realisation of this survey was affordable, thanks to the availability of corporate e-mail for each employee, intranet service, and company internal mail service. A dedicated web procedure and e-questionnaires allowed to automatically manage the contact with employees and to collect their data, which were both cost- and time-saving. Using this e-mail contact approach, 53% of contacted employees consented to participate in the survey. Radon concentration passive measuring devices were distributed to about 7000 dwellings, using about 14000 CR-39 detectors (two measured rooms per dwelling). In order to reduce costs, the devices were exposed for 12 months instead of two consecutive 6-month periods (as with the former national survey). A first checking of the actual representativeness of the sample was done by comparing characteristics of dwellings and occupants in the sample with corresponding data from the latest National Census. This was accomplished thanks to the fact that the questions in the survey questionnaire were tailored to the categories adopted for the Census questionnaire. A preliminary comparison showed that, at national level, the Italian dwellings are quite well represented by the sample. ► In Italy a new national survey was designed and organised. ► A new approach for a proxy of a representative national survey was used. ► The aim is to estimate the frequency distribution of indoor radon concentration in all the 110 Italian Provinces. ► The realisation of this survey was feasible and affordable. ► Preliminary evaluation of sample representativeness was performed at national level.

An Assessment of Clinical Performance Measures for Pediatric Emergency Physicians

The objectives were to evaluate clinical performance measures used for pediatric emergency medicine (PEM) physicians for reliability, correlation with one another, and relationship with clinical experience. This retrospective cohort study collected performance data for PEM physicians working at an urban children's hospital emergency department (ED) for each of 7 consecutive 6-month periods. Low correlations were seen between patients per hour or admission rate and 72-hour revisit rates. No significant association existed between level of experience and any performance measure. Physician treatment times appeared to be most reliable, and revisit rates were least reliable. Increase in number of patients seen per hour or lower admission rates in the ED are not significantly associated with an increase in revisit rates. Provider experience did not affect performance measures. Physician treatment time, patients per hour, admission rate, and charges per hour are reliable measures to assess the clinical performance of PEM physicians working at a single center.

EP News: Clinical

Thibault and colleagues (Circulation 2011; 124(25):2874–2881. PMID: 22104549) compared the effects of LV and biventricular (BiV) pacing on exercise tolerance and LV remodeling in patients with an LVEF ≤35%, QRS ≥120 msec, and heart failure in a multicenter, double-blind randomized trial. 121 patients were randomized to LV followed by BiV pacing or vice versa for consecutive 6-month periods. Exercise duration at 75% of peak Vo(2) (primary outcome) increased from 9.3 ± 6.4 to 14.0 ± 11.9 and 14.3 ± 12.5 minutes with LV and BiV pacing, respectively (P = 0.4).

Left Ventricular Versus Simultaneous Biventricular Pacing in Patients With Heart Failure and a QRS Complex ≥120 Milliseconds

Left ventricular (LV) pacing alone may theoretically avoid deleterious effects of right ventricular pacing. In a multicenter, double-blind, crossover trial, we compared the effects of LV and biventricular (BiV) pacing on exercise tolerance and LV remodeling in patients with an LV ejection fraction ≤35%, QRS ≥120 milliseconds, and symptoms of heart failure. A total of 211 patients were recruited from 11 centers. After a run-in period of 2 to 8 weeks, 121 qualifying patients were randomized to LV followed by BiV pacing or vice versa for consecutive 6-month periods. The greatest improvement in New York Heart Association class and 6-minute walk test occurred during the run-in phase before randomization. Exercise duration at 75% of peak Vo(2) (primary outcome) increased from 9.3±6.4 to 14.0±11.9 and 14.3±12.5 minutes with LV and BiV pacing, respectively, with no difference between groups (P=0.4327). LV ejection fraction improved from 24.4±6.3% to 31.9±10.8% and 30.9±9.8% with LV and BiV pacing, respectively, with no difference between groups (P=0.4530). Reductions in LV end-systolic volume were likewise similar (P=0.6788). The proportion of clinical responders (≥20% increase in exercise duration) to LV and BiV pacing was 48.0% and 55.1% (P=0.1615). Positive remodeling responses (≥15% reduction in LV end-systolic volume) were observed in 46.7% and 55.4% (P=0.0881). Overall, 30.6% of LV nonresponders improved with BiV and 17.1% of BiV nonresponders improved with LV pacing. LV pacing is not superior to BiV pacing. However, nonresponders to BiV pacing may respond favorably to LV pacing, suggesting a potential role as tiered therapy. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00901212.

The cost of providing comprehensive HIV treatment in PEPFAR-supported programs

PEPFAR, national governments, and other stakeholders are investing unprecedented resources to provide HIV treatment in developing countries. This study reports empirical data on costs and cost trends in a large sample of HIV treatment sites. In 2006-2007, we conducted cost analyses at 43 PEPFAR-supported outpatient clinics providing free comprehensive HIV treatment in Botswana, Ethiopia, Nigeria, Uganda, and Vietnam. We collected data on HIV treatment costs over consecutive 6-month periods starting from scale-up of dedicated HIV treatment services at each site. The study included all patients receiving HIV treatment and care at study sites [62,512 antiretroviral therapy (ART) and 44,394 pre-ART patients]. Outcomes were costs per patient and total program costs, subdivided by major cost categories. Median annual economic costs were US$ 202 (2009 USD) for pre-ART patients and US$ 880 for ART patients. Excluding antiretrovirals, per patient ART costs were US$ 298. Care for newly initiated ART patients cost 15-20% more than for established patients. Per patient costs dropped rapidly as sites matured, with per patient ART costs dropping 46.8% between first and second 6-month periods after the beginning of scale-up, and an additional 29.5% the following year. PEPFAR provided 79.4% of funding for service delivery, and national governments provided 15.2%. Treatment costs vary widely between sites, and high early costs drop rapidly as sites mature. Treatment costs vary between countries and respond to changes in antiretroviral regimen costs and the package of services. Whereas cost reductions may allow near-term program growth, programs need to weigh the trade-off between improving services for current patients and expanding coverage to new patients.

Fresh blood for transfusion in adults with beta thalassaemia

Patients with beta-thalassaemia major require life-long blood transfusion with the aim of achieving normal growth and development whilst minimising iron overload. A pre-transfusion Hb between 9.5 and 10 g/dL is thought to achieve this balance. UK consensus is that fresh blood (less than 14 days) is better at maintaining this target pre-transfusion Hb but there is no firm stipulation in place and no robust evidence supporting this. After introduction of a universal fresh blood policy for adult beta-thalassaemics in 2010, we reviewed locally transfused adult patients to determine if there was any significant difference in pre-transfusion Hb using fresh blood. Nine adult thalassaemic patients were analysed for two consecutive 6-month periods in 2009 and 2010 (periods 1 and 2). Mean pre-transfusion Hb was significantly higher by an average of 0.5 g/dL in period 2 than period 1 (P < 0.05). The average unit age was 18 vs 9.5 days for periods 1 and 2 respectively (P < 0.05). There were no significant differences in potential confounders such as transfusion volume (P = 0.06), number of units transfused, ferritin or transfusion interval. Use of fresh blood produced significantly higher pre-transfusion Hb, giving credence to UK consensus. Lesser volumes of fresh blood appeared to achieve the target pre-transfusion Hb, which may translate to reduced iron overload and chelation costs. Whether the assumption that the use of blood less than 7 days old in these patients would result in greater benefit requires further study.

Point-of-Care Electronic Prompts

Incentives based on quality indicators such as the Surgical Care Improvement Project core measures (SCIP 1) encourage implementation of evidence-based guidelines consistently into clinical practice. Information systems with point-of-care electronic prompts (POCEPs) can facilitate adoption of processes and benchmark performance. We evaluated the effectiveness of POCEPs on rates of antibiotic administration within 60 minutes of surgical incision and effect on outcome in a prospective observational trial. SCIP 1 compliance and the corresponding outcome variable (surgical site infection [SSI]) were examined prospectively over 2 consecutive 6-month periods before (A) and after (B) POCEPs implementation at a regional health system. Secondary analysis extended the observation to two 12-month periods (A' and B'). A 2-year (C and D) sustainability phase followed. The 19,744 procedures included 9127 and 10,617 procedures before (A) and after (B) POCEPs implementation, respectively. POCEPs increased compliance with SCIP indicators in period B by 31% (95% CI, 30.0%-32.2%) from 62% to 92% (P < 0.001) and were associated with a sustainable, contemporaneous decrease in the incidence of SSI from 1.1% to 0.7% (P = 0.003; absolute risk reduction, 0.4%; 95% CI, 0.1%-0.7%). Secondary and sustainability analysis revealed that compliance rates remained >95% with mean SSI rates lower for all periods compared with pre-POCEPs SSI rates (0.8%, 0.7%, and 0.5% vs 1.1%; P < 0.001). POCEPs increased compliance with SCIP indicators by >30% and were associated with a 0.4% absolute risk reduction in the incidence of SSI. POCEPs may be useful to modulate provider behavior and demonstrate intraoperative quality and value.

Assessment of long-term radon concentration measurement precision in field conditions (Serbian Schools) for a survey carried out by an international collaboration

In an international collaboration, a long-term radon concentration survey was carried out in schools of Southern Serbia with radon detectors prepared, etched and read-out in Italy. In such surveys it is necessary to evaluate measurement precision in field conditions, and to check whether quality assurance protocols were effective in keeping uncertainties under control, despite the complex organisation of measurements. In the first stage of the survey, which involves only some of the total number of municipalities, paired detectors were exposed in each monitored room in order to experimentally assess measurement precision. Paired passive devices (containing CR-39 detectors) were exposed for two consecutive 6-month periods. Two different measurement systems were used to read out CR-39s of the first and second period, respectively. The median of the coefficient of variation (CV) of the measured exposures was 8 % for 232 paired devices of the first 6-month period and 4 % for 242 paired devices of the second 6-month period, respectively. This difference was mainly due to a different track count repeatability of the two read-out systems, which was 4 and 1 %, respectively, as the median value of CV of repeated countings. The in-field measured precision results are very similar to the precision assessed in calibration conditions and are much lower than the room-to-room variation of radon concentration in the monitored schools. Moreover, a quality assurance protocol was followed to reduce extra-exposures during detector transport from Rome to schools measured and back.

A claims‐based Markov model for Crohn’s disease

Crohn's disease is a chronic condition that often presents in early adulthood. To evaluate health care costs and costs per quality-adjusted life year (QALY) for Crohn's disease. A Markov model was developed using administrative claims data for patients aged > or = 18 years with > or = 3 years of continuous enrolment from 2000 to 2008 and > or =2 Crohn's disease claims. Disease states (remission, mild-moderate, moderate-severe, and severe-fulminant) were defined using the American College of Gastroenterology treatment guidelines criteria. Transition probabilities were calculated from consecutive 6-month periods. Costs were determined from paid claims and QALY utilities were obtained from the literature. The model assumed a 30-year-old patient at the time of entry into the model. There were 40 063 patients identified, with a total of 420 773 cycles [remission (197 111; 46.8%), mild-moderate (44 024; 10.5%), moderate-severe (132 695; 31.5%), severe-fulminant (46 925; 11.2%)]. The costs/QALY for remission, mild-moderate, moderate-severe, and severe-fulminant disease states respectively were $2896, $8428, $11 518 and $69 277 for males and $2896, $8426, $22 633 and $69 412 for females. Overall, health care costs for patients with Crohn's disease increased with disease severity. Although the probabilities of transitioning from other health states to the severe-fulminant disease state were low, the cost/QALY was high.

Trauma Attending Physician Continuity: Does it Make a Difference?

Continuity of care is important in achieving optimal outcomes in trauma patients, but the optimal length of the trauma attending (TA) rotation is unknown. We hypothesize that longer TA rotations provide greater continuity, and therefore improve outcomes. We did a retrospective comparison of trauma patient outcomes from two consecutive 6-month periods during which we transitioned from a 1-month TA rotation to a 1-week TA rotation. The Wilcoxon rank sum test, and the chi2 were used for statistical analysis. Over the 12-month study period 1924 patients were admitted to the Trauma Service. The two groups were similar with regard to age, gender, injury mechanism, Injury Severity Score and Glasgow Coma Scale scores, and Abbreviated Injury Scores for the chest, abdomen, and extremities. Although mortality, patient charges, and violations of the standard of care were similar between the two groups, overall morbidity was lower (18.6% vs. 23.2%), and hospital length of stay higher (9.07 days vs. 8.41 days) in the 1-week TA group compared with the 1-month TA group. A one-week TA rotation was associated with a longer hospital length of stay, but improved morbidity. Longer TA rotations do not necessarily provide improved continuity or improved outcomes.

Demographic, Psychological, and Behavioral Modifiers of the Antiretroviral Treatment Access Study (ARTAS) Intervention

The present study sought to identify demographic, structural, behavioral, and psychological subgroups for which the Antiretroviral Treatment Access Study (ARTAS) intervention had stronger or weaker effects in linking recently diagnosed HIV-positive persons to medical care. The study, carried out from 2001 to 2003, randomized 316 participants to receive either passive referral or a strengths-based linkage intervention to facilitate entry into HIV primary care. The outcome was attending at least one HIV primary care visit in each of two consecutive 6-month periods. Participants (71% male; 29% Hispanic; 57% black non-Hispanic), were recruited from sexually transmitted disease clinics, hospitals and community-based organizations in four U.S. cities. Thirteen effect modifier variables measured at baseline were examined. Subgroup differences were formally tested with interaction terms in unadjusted and adjusted log-linear regression models. Eighty-six percent (273/316) of participants had complete 12-month follow-up data. The intervention significantly improved linkage to care in 12 of 26 subgroups. In multivariate analysis of effect modification, the intervention was significantly (p < 0.05) stronger among Hispanics than other racial/ethnic groups combined, stronger among those with unstable than stable housing, and stronger among those who were not experiencing depressive symptoms compared to those who were. The ARTAS linkage intervention was successful in many but not all subgroups of persons recently diagnosed with HIV infection. For three variables, the intervention effect was significantly stronger in one subgroup compared to the counterpart subgroup. To increase its scope, the intervention may need to be tailored to the specific needs of groups that did not respond well to the intervention.

Nine-year trends in clinically relevant reduced susceptibility of HIV-1 to antiretrovirals

Background Temporal changes in HIV-1 resistance both reflect and influence the clinical use of antiretrovirals (ARVs). Objective To determine temporal trends in reduced susceptibility to ARVs and resistance mutations in routine clinical samples (RCS) from HIV infected patients. Study design Calculated fold-changes (FC) for ARVs were determined for viral genotypes from RCS received between July 1998 and June 2007 using vircoTYPE HIV-1 (Version 4.2.01). The prevalence of isolates with clinically relevant reduced susceptibility and of resistance mutations were determined for consecutive 6-month periods. Results 242,003 RCS were identified. The prevalence of RCS exhibiting reduced susceptibility to ≥1 drug among any of three ARV classes decreased from 82% to 66.5% and of these, to ≥1 drug in each of the three ARV classes and from 30.5% to 15.7% from December 98 to June 07 ( p ≤ 0.0001). The prevalence of mutations associated with NRTI, NNRTI and PI resistance generally reflected evolving use of these drug classes. Among fully susceptible RCS, isolates that exhibited resistance mutations were rare. Conclusions Clinically relevant reduced susceptibility to ARVs declined over the 9-year period. There was a general higher prevalence of reduced susceptibility to RT inhibitors than to PIs.

Radon concentrations in schools of the Neapolitan area

A radon survey was carried out in 30 schools located in the metropolitan area around Naples, Italy. Radon concentration was measured using the SSNTD (Solid State Nuclear Track Detectors) method with LR115 detectors. Time integrated measurements covered two consecutive 6-month periods at different locations inside the school buildings: classrooms, laboratories and offices. Data distribution is well fitted by a log-normal curve. The arithmetic mean annual radon concentration is 144 Bq m −3, the geometric mean is 86 Bq m −3; the standard deviations are respectively 7 Bq m −3 and 3. The fractions of rooms where radon concentrations exceed the reference levels of 200, 400 and 500 Bq m −3 are 21.3%, 7.6% and 4.5% respectively. The results show that radon concentration in scientific laboratories and in offices is higher than in classrooms.

The Association Between Changes in Health Status and Nursing Home Resident Quality of Life

Previous research on nursing home resident quality of life (QOL) has mainly been cross-sectional. This study examined the association between changes in QOL and changes in resident clinical factors. A longitudinal study of resident QOL was conducted in two nursing homes. Self-report interviews using a multidimensional measure of QOL were linked with clinical data from the Minimum Data Set. Five waves of interviews were conducted at 6-month intervals. Residents with one or more Stage II or higher pressure ulcers for two consecutive 6-month periods reported declines in autonomy, security, and spiritual well-being QOL domains; those with declines in physical disability reported declines in the dignity domain. Increases in depressive symptoms were associated with decreases in comfort, meaningful activities, and food enjoyment domains, and increases in pain were associated with decreases in functional competence and dignity domains. There is evidence of an association between physical health and self-reported QOL. However, not every dimension of QOL exhibited the same pattern. Further research is needed on the link between specific clinical factors and aspects of QOL.

Use of a Computerized Forcing Function Improves Performance in Ordering Restraints

We evaluate the effect of a computerized order entry system forcing function on improving timely renewal of restraint orders. In this prospective study of 2 successive interventions, physicians received computerized reminders to renew or discontinue restraint orders before their expiration. The initial intervention allowed acknowledgement of this reminder without further consequence, changing at 6 months to deny computer access until addressed. We performed chart review on emergency department visits with restraint orders in 3 consecutive 6-month periods (A, B, C) separated by these 2 interventions, determining time to order renewal, number of restraint orders, renewal orders per hour in restraints, and time in restraints and evaluating variability in these values across study intervals. Statistical analysis for our primary outcome used the Mann-Whitney and variance ratio tests. Median time to order renewal decreased in periods B and C versus A by 64 and 56 minutes, respectively, with variability in this measure decreasing across all periods. Mean number of restraint orders in periods B and C significantly increased versus those in A (1.46 to 1.89 to 2.34), with corresponding increases in variability. Mean renewal orders per hour in restraint significantly increased in period C versus A and B, from 0.08 to 0.23 to 0.89, with increasing variability across all periods. Decreases in median time spent in restraints observed in periods B and C versus A of 45 and 105 minutes, respectively, trended toward but did not achieve significance, with significantly decreasing variability compared with baseline. The forcing function improved restraint reordering and variability in practice and may have contributed to nonsignificant reductions observed in time in restraint.

Minimal disease activity, remission, and the long‐term outcomes of rheumatoid arthritis

To determine the prevalence of minimal disease activity (MDA) and remission in patients with rheumatoid arthritis (RA), to assess the effect of anti-tumor necrosis factor (anti-TNF) therapy on MDA, and to determine the extent to which MDA status improves long-term outcomes. Using the Patient Activity Scale (PAS) as a surrogate, we assessed the prevalence of MDA and remission in 18,062 patients with RA using the newly developed Outcome Measures in Rheumatology Clinical Trials (OMERACT) criteria for MDA. MDA was noted in 20.2% of 18,062 patients and persistent MDA, operationally defined as having MDA during >or=2 consecutive 6-month observation periods, occurred in 13.5% of 7,433 patients followed longitudinally. Disease activity at remission levels was noted in 7%. Among patients with MDA, 82% received disease-modifying antirheumatic drugs or biologic agents. Following anti-TNF initiation, the cumulative probability of achieving MDA at 2 and 6 years was 4.1% and 7.6%, respectively, and persistent MDA probabilities were 2.7% and 4.5%, respectively. Regardless of RA duration, patients with MDA had substantially better outcomes, including a 10-fold reduction in work disability and an approximately 2-fold reduction in total joint replacement and mortality. Remission remains uncommon in RA, and the prevalence of new remission in community practice is substantially lower than noted in published trials of biologic therapy. On average, persons with MDA appear to have persistently mild RA. This might be the effect of milder RA and/or more effective treatment in early RA. The PAS had satisfactory levels of agreement with the full MDA criteria and appears suitable for use in clinical and epidemiologic research.

Psychological and Behavioral Correlates of Entering Care for HIV Infection: The Antiretroviral Treatment Access Study (ARTAS)

The present study sought to examine psychological and behavioral variables as predictors of attending an HIV medical care provider among person's recently diagnosed with HIV. The study, carried out between 2001 and 2003, was a two-arm randomized intervention trial with participants recruited from public HIV testing centers, sexually transmitted disease (STD) clinics, hospitals, and community-based organizations in Atlanta, Georgia; Baltimore, Maryland; Miami, Florida; and Los Angeles, California. Eighty-six percent of those enrolled (273) had complete baseline and 12-month follow-up data. Measures of number of months since HIV diagnosis, readiness to enter care (based on stages of change), barriers and facilitators to entering care, drug use, and intervention arm (case managed versus simple referral) were examined as predictors of attending an HIV care provider, defined as being in care at least once in each of two consecutive 6-month follow-up periods. In logistic regression, seeing a care provider was significantly more likely among participants diagnosed with HIV within 6 months of enrollment (odds ratio [OR] = 2.52, 95% confidence interval [CI], 1.25, 5.06), those in the preparation versus precontemplation stages at baseline (OR = 2.87, 95% CI, 1.21, 6.81), those who reported at baseline that someone (friend, family member, social worker, other) was helping them get into care (OR = 2.13, 95% CI, 1.02, 4.44), and those who received a case manager intervention (OR = 2.16, 95% CI, 1.23, 3.78). The findings indicate a need to reach HIV-positive person's soon after diagnosis and assist them in getting into medical care. Knowing a person's stages of readiness to enter care and their support networks can help case managers formulate optimal client plans.

Setting Control Limits for Escherichia coli Counts in Samples Collected Routinely from Pig or Beef Carcasses

Records of Escherichia coli counts in samples routinely collected from carcasses were obtained from one pork and three beef packing plants. The data obtained from each plant were divided into sets from consecutive 6-month periods. For each set of counts, log total counts were calculated for subsets of various sizes. For each set of log total counts, the mean (x̄), the standard deviation (SD), and an action limit of x̄ + 3 SD were calculated, and the set was tested for a normal distribution. With the data from samples collected at the pork packing plant during 6 years, the proportion of samples with counts of zero in the 12 sets ranged from 15 to 45%. For that plant, appropriate action limits could be derived from log total counts for subsets of nine unit values. With the data from samples collected during 8 years at one beef packing plant, the proportion of samples with counts of zero in the 16 sets ranged from 88 to 99%. For that plant, appropriate action limits could be derived from log total counts for subsets of 15 unit values. With the data from samples collected during 2 or 2.5 years at each of the other beef packing plants, the proportion of samples with counts of zero in all sets was >99%. For those data, action limits could not be derived from values for subsets of log total counts.

Annual average and seasonal variations of residential radon concentration for all the Italian Regions

A representative National Survey to evaluate the exposure to natural sources of ionizing radiation in dwellings was conducted in all the 21 Italian Regions from 1989 to 1998, and the complete results are reported in this paper. Radon concentration was measured for two consecutive 6-month periods (generally covering the spring–summer and autumn–winter seasons) in one room, usually the main bedroom, of each surveyed dwelling. Validated radon concentration measurements were obtained for a total of 5631 dwellings, distributed in 232 towns (all the 50 towns with more than 100,000 inhabitants and 182 randomly sampled smaller towns). The national average, weighted by the population of each Region, of the annual radon concentration is 70 Bq m - 3 , the geometric mean is 52 Bq m - 3 , and the geometric standard deviation is 2.1. The fraction of dwellings with a radon concentration exceeding the reference levels of 150, 200, 400, and 600 Bq m - 3 are 7.7%, 4.1%, 0.9%, and 0.2%, respectively. Regional averages ranged from about 25 Bq m - 3 to about 120 Bq m - 3 . The uncertainty of regional values can be relevant in the case of small Regions, where few small towns were sampled, however such uncertainties do not affect national values significantly. A log-normal model underestimates the fraction of dwellings with high radon concentration and needs to be adjusted to obtain a better fitting. Two complete 6-month measurements were obtained for 4742 dwellings. The regional values of the geometric mean and of the geometric standard deviation of the winter/summer ratio ranged from 0.81 to 2.58 and from 1.32 to 1.88, respectively. The corresponding national values were 1.23 and 1.71, respectively. These results and their implications are discussed in the paper.