Ixazomib, Lenalidomide, and Dexamethasone (IRD) Treatment with Cytogenetic Risk-Based Maintenance in Transplant-Eligible Myeloma: A Phase 2 Multicenter Study by the Nordic Myeloma Study Group.

Scarce data exist on double maintenance in transplant-eligible high-risk (HR) newly diagnosed multiple myeloma (NDMM) patients. This prospective phase 2 study enrolled 120 transplant-eligible NDMM patients. The treatment consisted of four cycles of ixazomib-lenalidomide-dexamethasone (IRD) induction plus autologous stem cell transplantation followed by IRD consolidation and cytogenetic risk-based maintenance therapy with lenalidomide + ixazomib (IR) for HR patients and lenalidomide (R) alone for NHR patients. The main endpoint of the study was undetectable minimal residual disease (MRD) with sensitivity of <10-5 by flow cytometry at any time, and other endpoints were progression-free survival (PFS) and overall survival (OS). We present the preplanned analysis after the last patient has been two years on maintenance. At any time during protocol treatment, 28% (34/120) had MRD < 10-5 at least once. At two years on maintenance, 66% of the patients in the HR group and 76% in the NHR group were progression-free (p = 0.395) and 36% (43/120) were CR or better, of which 42% (18/43) had undetectable flow MRD <10-5. Altogether 95% of the patients with sustained MRD <10-5, 82% of the patients who turned MRD-positive, and 61% of those with positive MRD had no disease progression at two years on maintenance (p < 0.001). To conclude, prolonged maintenance with all-oral ixazomib plus lenalidomide might improve PFS in HR patients.

Efficacy of conventional-dose cytarabine, idarubicin and thioguanine versus intermediate-dose cytarabine and idarubicin in the induction treatment of acute myeloid leukemia: Long-term results of the prospective randomized nationwide AML-2003 study by the Finnish Leukemia Group.

OBJECTIVES: AML-2003 study sought to compare the long-term efficacy and safety of IAT and IdAraC-Ida in induction chemotherapy of acute myeloid leukemia (AML) and introduce the results of an integrated genetic and clinical risk classification guided treatment strategy. METHODS: Patients were randomized to receive either IAT or IdAraC-Ida as the first induction treatment. Intensified postremission strategies were employed based on measurable residual disease (MRD) and risk classification. Structured questionnaire forms were used to gather data prospectively. RESULTS: A total of 356 AML patients with a median age of 53 years participated in the study. Long-term overall survival (OS) and relapse-free survival (RFS) were both 49% at 10 years. The median follow-up was 114 months. No significant difference in remission rate, OS or RFS was observed between the two induction treatments. Risk classification according to the protocol, MRD after the first and the last consolidation treatment affected the OS and RFS significantly (p < .001). CONCLUSIONS: Intensified cytarabine dose in the first induction treatment was not better than IAT in patients with AML. Intensification of postremission treatment in patients with clinical risk factors or MRD seems reasonable, but randomized controlled studies are warranted in the future.

RVD induction and autologous stem cell transplantation followed by lenalidomide maintenance in newly diagnosed multiple myeloma: a phase 2 study of the Finnish Myeloma Group.

Autologous stem cell transplantation (ASCT) combined with novel agents is the standard treatment for transplant-eligible, newly diagnosed myeloma (NDMM) patients. Lenalidomide is approved for maintenance after ASCT until progression, although the optimal duration of maintenance is unknown. In this trial, 80 patients with NDMM received three cycles of lenalidomide, bortezomib, and dexamethasone followed by ASCT and lenalidomide maintenance until progression or toxicity. The primary endpoint was the proportion of flow-negative patients. Molecular response was assessed if patients were flow-negative or in stringent complete response (sCR). By intention to treat, the overall response rate was 89%. Neither median progression-free survival nor overall survival (OS) has been reached. The OS at 3 years was 83%. Flow-negativity was reached in 53% and PCR-negativity in 28% of the patients. With a median follow-up of 27 months, 29 (36%) patients are still on lenalidomide and 66% of them have sustained flow-negativity. Lenalidomide maintenance phase was reached in 8/16 high-risk patients but seven of them have progressed after a median of only 6 months. In low- or standard-risk patients, the outcome was promising, but high-risk patients need more effective treatment approach. Flow-negativity with the conventional flow was an independent predictor for longer PFS.

Residual disease detected by flow cytometry is an independent predictor of survival in childhood acute myeloid leukaemia; results of the NOPHO-AML 2004 study.

Early response after induction is a prognostic factor for disease outcome in childhood acute myeloid leukaemia (AML). Residual disease (RD) detection by multiparameter flow cytometry (MFC) was performed at day 15 and before consolidation therapy in 101 patients enrolled in the Nordic Society of Paediatric Haemato-Oncology AML 2004 study. A multicentre laboratory approach to RD analysis was used. Event-free survival (EFS) and overall survival (OS) was significantly different in patients with and without RD at both time points, using a 0·1% RD cut-off level. RD-negative and -positive patients after first induction showed a 5-year EFS of 65 ± 7% and 22 ± 7%, respectively (P < 0·001) and an OS of 77 ± 6% (P = 0·025) and 51 ± 8%. RD-negative and -positive patients at start of consolidation therapy had a 5-year EFS of 57 ± 7% and 11 ± 7%, respectively (P < 0·001) and an OS of 78 ± 6% and 28 ± 11%) (P < 0·001). In multivariate analysis only RD was significantly correlated with survival. RD before consolidation therapy was the strongest independent prognostic factor for EFS [hazard ratio (HR):5·0; 95% confidence interval (CI):1·9-13·3] and OS (HR:7·0; 95%CI:2·0-24·5). In conclusion, RD before consolidation therapy identifies patients at high risk of relapse in need of intensified treatment. In addition, RD detection can be performed in a multicentre setting and can be implemented in future trials.

Bacterial infection (BI)-INDEX: an improved and simplified rapid flow cytometric bacterial infection marker.

The aim of this study was to develop a rapid and simple flow cytometric bacterial infection marker. In this prospective comparative study, quantitative flow cytometric analysis of CD10, CD35, CD66b, CD282, and MHC Class I molecules on human neutrophils, monocytes, and B-lymphocytes from 141 hospitalized febrile patients with suspected infection and from 50 healthy controls was performed. We developed a flow cytometric marker of local and systemic bacterial infections, designated "bacterial infection (BI)-INDEX", incorporating the quantitative analysis of CD10, CD35, MHCI, CD66b, and CD282 on neutrophils, monocytes, and B-lymphocytes, which displayed 90% sensitivity and 96% specificity in distinguishing between microbiologically confirmed bacterial (n = 31) and viral infections (n = 27) within a 1-h time-frame. We propose that our novel rapid BI-INDEX test will be useful in assisting physicians to ascertain whether antibiotic treatment is required, thus limiting unnecessary antimicrobial usage.

Use of complement regulators, CD35, CD46, CD55, and CD59, on leukocytes as markers for diagnosis of viral and bacterial infections.

Several complement regulatory proteins exist on self-cells to prevent damage by the serum complement system. In the present study, we aimed to perform quantitative analysis of membrane-bound complement regulators, CR1 (CD35), MCP (CD46), DAF (CD55), and MIRL (CD59), on peripheral blood neutrophils, monocytes, and lymphocytes from healthy controls (n=36) and febrile patients diagnosed with either bacterial (n=21) or viral (n=26) infections. Our results show that: (a) increased CD35 and CD55 levels on neutrophils and monocytes present potent markers of bacterial infection, (b) increased expression of CD46 on monocytes is an indicator of viral infection, and (c) increased CD59 expression on neutrophils and monocytes is a general infection marker. Additionally, CD19-positive B-lymphocytes represent practically the only lymphocyte population capable of expressing CD35. We further developed two novel clinical flow cytometric markers (indices), specifically, clinical mononucleosis (CM)-INDEX (incorporating CD35, CD55, and CD59 expression on lymphocytes) and clinical bacterial infection (CBI)-INDEX (incorporating CD35 and CD55 expression on neutrophils and lymphocytes), for the effective detection of viral mononucleosis and bacterial infection, respectively. In summary, bacterial and viral infections induce different expression patterns of membrane-bound complement regulators in human leukocytes, which may be effectively exploited in clinical differential diagnosis.

A rapid flow cytometric method for distinguishing between febrile bacterial and viral infections.

Antibiotic resistance due to the inappropriate use of antimicrobials is one of the most critical public health problems worldwide. A major factor underlying the unnecessary use of antibiotics is the lack of rapid and accurate diagnostic tests. Therefore, we aimed to develop a novel rapid flow cytometric method for distinguishing between febrile bacterial and viral infections. In this prospective comparative study, quantitative flow cytometric analysis of FcγRII/CD32, CR1/CD35, MHC Class I receptor (MHCI), and C5aR/CD88 on human phagocytes was performed in 286 hospitalized febrile patients with suspected infection. After using microbiological and serological detection methods, or clinical diagnosis, 205 patients were identified with either bacterial (n=136) or viral (n=69) infection. Receptor data from patients were compared to those of 50 healthy controls. We developed a flow cytometric marker of local and systemic bacterial infections designated "bacterial infection score (BIS)" incorporating the quantitative analysis of FcγRII/CD32, CR1/CD35, C5aR/CD88 and MHCI on neutrophils and/or monocytes, which displays 91% sensitivity and 92% specificity in distinguishing between microbiologically confirmed bacterial (n=77) and serologically confirmed viral infections (n=61) within 1h. The BIS method was effectively applied to distinguish between bacterial and viral (pandemic H1N1 influenza) pneumonia cases with 96% sensitivity and 92% specificity. We propose that the rapid BIS test can assist physicians in deciding whether antibiotic treatment is necessary, thus reducing unnecessary antimicrobial use.

Depth of response assessed by quantitative ASO-PCR predicts the outcome after stem cell transplantation in multiple myeloma.

Achievement of complete response (CR) is a new goal of therapy for multiple myeloma (MM). By sensitive methods, the depth of response can be measured even among the patients in CR. We used a sensitive real-time quantitative polymerase chain reaction by allele-specific primers (qASO-PCR) to assess the level of minimal residual disease (MRD) in bone marrow of 37 patients with myeloma who had achieved CR/near-to-CR after autologous or allogeneic stem cell transplantation (SCT). Allele-specific primers could be successfully designed for 86% of patients. Three to six months after autotransplantation, the PCR target was not detectable in 53% of patients (16/30 patients), and the respective figure after allotransplantation was 71% (5/7 patients); the median sensitivity of PCR assay was <0.002%. The proportion of patients without detectable PCR target was 22% of all autotransplanted patients. A threshold level of 0.01% in the qASO-PCR assay 3-6 months after SCT was found to be a useful cut-off limit to divide the patients into two prognostic groups: MRD low/negative vs. MRD high. Low/negative MRD after SCT was a significant predictive factor for the prolongation of progression free (70 vs. 19 months; P = 0.003) and suggestively also for overall survival. We conclude that not only CR but also its depth is important for the long-term outcome in MM.

Prognostic evaluation of COX-2 expression in renal cell carcinoma.

BACKGROUND: Prognosis of renal cell carcinoma (RCC) differs within the same stage and grade. Our aim was to investigate the incidence of COX-2 in primary RCC tumors at different stages according to the occurrence of metastasis, and the impact of this biomarker on the survival of RCC patients. PATIENTS AND METHODS: The cytoplasmic/membranous COX-2 protein expression was examined by immunohistochemistry in RCC tumors from 102 patients. The patients were divided into those with: no metastasis during 7.5 years' follow-up (nm), no metastasis at the time of nephrectomy but who later developed metastases (lm), and those with metastasis at presentation (pm). The immunoreactivity of COX-2 was classified as none (absent/weak intensity in fewer than 10% of the cancer cells), low (weak intensity in over 10% of the cancer cells) or high immunostaining (strong intensity in the majority of the cancer cells). In addition p53 and Ki-67 immunostaining was also assessed in tumors. RESULTS: Percentages of COX-2 reaction were (no/low/high): 78/16/7 in the nm, 53/28/19 in the lm, 92/8/0 in the pm groups (p=0.014). Median metastasis-free survival was shorter in lm patients with COX-2-negative tumors when compared to those with COX-2-positive ones (15 vs. 46 months; p=0.020). Median overall survival was shorter in pm/lm patients with COX-2-negative tumors when compared to those with COX-2-positive ones (28 vs. 94 months; p=0.027), and with COX-2-negative/Ki-67-positive tumors when compared to COX-2-positive/Ki-67-negative ones (19 vs. 97 months; p=0.004). Findings for patients with COX-2-negative/p53-positive tumors were similar, with shorter survival compared to those with COX-2-positive/p53-negative ones (19 vs. 97; p=0.006). CONCLUSION: COX-2 protein expression is associated with slow development of metastases, and favourable prognosis in metastatic RCC.

Evaluation of the effects of different transfusion trigger levels during the treatment of childhood acute lymphoblastic leukemia.

Differences in the triggering levels for red blood cell (RBC) and platelet (PLT) transfusions were analyzed in association to the amount and total costs of transfusions and the number of febrile episodes during childhood acute lymphoblastic leukemia (ALL) treatment. Transfusions are given with hemoglobin (Hb) < or =90 to 100 g/L and PLT count < or =20 to 30 x 10(9)/L in Tampere, and with Hb < or =80 g/L and PLT count < or =10 x 10(9)/L in Turku. Median pretransfusion PLT count was 48 x 10(9)/L in Tampere, and 16 x 10(9)/L in Turku. The number and costs of PLT transfusions were 35% higher in Tampere. Median Hb before transfusion was 95 g/L in Tampere, and 77 g/L in Turku. The costs of RBC transfusions were 29% lower in Turku as child units (90 mL) were preferred. The number of RBC transfusions was associated with the treatment protocol (P=0.001), and PLT transfusions with the treatment protocol (P<0.001) and the treatment center (P=0.04). The number of febrile episodes was associated with the treatment protocol (P=0.03), and age at diagnosis (P=0.07). Lower trigger levels did not cause more delays or complications in treatment. Clinical trials are, however, necessary to determine optimal criteria for supportive blood transfusions in childhood cancer patients.

Absence of polysialylated NCAM is an unfavorable prognostic phenotype for advanced stage neuroblastoma.

BACKGROUND: The expression of a neural crest stem cell marker, polysialic acid (polySia), and its main carrier, neural cell adhesion molecule (NCAM), have been detected in some malignant tumors with high metastatic activity and unfavorable prognosis, but the diagnostic and prognostic value of polySia-NCAM in neuroblastoma is unclear. METHODS: A tumor tissue microarray (TMA) of 36 paraffin-embedded neuroblastoma samples was utilized to detect polySia-NCAM expression with a polySia-binding fluorescent fusion protein, and polySia-NCAM expression was compared with clinical stage, age, MYCN amplification status, histology (INPC), and proliferation index (PI). RESULTS: PolySia-NCAM-positive neuroblastoma patients had more often metastases at diagnosis, and polySia-NCAM expression associated with advanced disease (P = 0.047). Most interestingly, absence of polySia-NCAM-expressing tumor cells in TMA samples, however, was a strong unfavorable prognostic factor for overall survival in advanced disease (P = 0.0004), especially when MYCN was not amplified. PolySia-NCAM-expressing bone marrow metastases were easily detected in smears, aspirates and biopsies. CONCLUSION: PolySia-NCAM appears to be a new clinically significant molecular marker in neuroblastoma, hopefully with additional value in neuroblastoma risk stratification.

Single-dose pegfilgrastim is comparable to daily filgrastim in mobilizing peripheral blood stem cells: a case-matched study in patients with lymphoproliferative malignancies.

Pegfilgrastim (PEGFIL) has been found to be comparable to daily filgrastim (FIL) in managing chemotherapy-induced neutropenia. In the present study, we evaluated the ability of PEGFIL to mobilize stem cells in 38 consecutive patients with lymphoproliferative diseases (multiple myeloma, n = 18; lymphomas, n = 15; chronic lymphocytic leukemia, n = 5). Patients were mobilized using PEGFIL (6-18 mg as a single dose) during 2005-2006; 32 then received high-dose chemotherapy followed by autologous stem cell transplantation. PEGFIL-mobilized patients were matched by age, disease, and treatment line at a ratio of 1:2 to historical FIL-mobilized controls. The primary study endpoint was the blood CD34(+) concentration at onset of leukapheresis. Leukapheresis began a median of 10 days from the beginning of mobilization chemotherapy in both groups. At the onset of leukapheresis, median blood CD34(+) cell counts did not differ significantly in the FIL group compared with the PEGFIL group (79 x 10(6)/L vs 64 x 10(6)/L, respectively; p = 0.44). In the different disease categories, the respective CD34(+) cell counts after FIL and PEGFIL mobilization were 72 x 10(6)/L vs 123 x 10(6)/L (p = 0.08) in myeloma, 51 x 10(6)/L vs 62 x 10(6)/L (p = 0.6) in lymphomas, and 27 x 10(6)/L vs 30 x 10(6)/L (p = 0.62) in CLL, respectively. The target CD34(+) cell yield was harvested with one leukapheresis in 53% of PEGFIL-mobilized patients. Engraftment after autografting did not differ significantly in the two groups. Stem cell mobilization with a single dose of PEGFIL was, therefore, comparable to that achieved using daily FIL in patients with lymphoproliferative diseases. PEGFIL is a more practical way to mobilize stem cells than daily FIL.

Stem cell transplantation in poor-risk chronic lymphocytic leukemia: assessment of post-transplant minimal residual disease using four- and six-color flow cytometry and allele-specific RQ-PCR.

A total of 178 bone marrow samples were taken for minimal residual disease (MRD) analysis after 34 stem cell transplantations for poor-risk chronic lymphocytic leukemia, and 86 of them were analyzed in parallel by flow cytometry and allele-specific oligonucleotide-PCR (ASO-PCR). ASO primer was successfully designed for all patients whose frozen diagnosis samples were available. Flow cytometry and ASO-PCR were concordant, i.e. both either positive or both negative, in 78% of the analyses. Flow cytometry did not detect MRD in any of the samples that were PCR-negative cases. In contrast, ASO-PCR detected MRD in samples that were negative for MRD by flow cytometry in 22% of the analyses. In one patient, the immunophenotype but not the IgV(H) gene sequence had changed during a course of the disease, and MRD could not be followed by flow cytometry. In the remaining cases, the discrepancy was due to a higher sensitivity of ASO-PCR. Autologous stem cell transplantation resulted in clinical complete response in 87% (20/23) of the patients. By flow cytometry, 35% (8/23) of autotransplanted patients became MRD-negative, but only 12.5% (2/16) PCR-negative (sensitivity of ASO-PCR <0.001 and <0.01, respectively). All allotransplanted patients achieved or maintained hematological CR, and five out of nine patients (56%) became PCR-negative (sensitivity of PCR between <0.001 and <0.003), two of them having non-myeloablative conditioning. None of the patients who became PCR-negative after allogeneic transplantation have relapsed.

Wilms tumour gene 1 overexpression in bone marrow as a marker for minimal residual disease in acute myeloid leukaemia.

OBJECTIVES: Wilms tumour gene 1 (WT1) is overexpressed in leucocytes of most acute myeloid leukaemia (AML) patients. However, the clinical relevance of WT1 gene expression as minimal residual disease (MRD) marker in AML has been questioned. METHODS: We determined the expression of WT1 gene in bone marrow (BM) mononuclear cells of 100 AML patients at diagnosis and compared it with other MRD markers during follow up in 16 patients using quantitative reverse transcription-polymerase chain reaction. RESULTS: The median WT1 gene expression was 9.7% of K562 cell line WT1 expression (lower quartile 1.5%, upper quartile 29.9%, n = 100) at diagnosis and, 0.053% (lower quartile 0.022%, upper quartile 0.125%, n = 87) in molecular or immunophenotypic remission. Median WT1 expression in control BM was 0.029% (lower quartile 0.013%, upper quartile 0.061%, n = 22). The upper 99% percentile of remission samples was 0.3%, which was regarded as the cut-off of increased WT1 gene expression in AML and was exceeded in 87% of all AML patients at diagnosis. WT1 and the other MRD markers showed only minor differences in profiles during follow-up. WT1 expression at diagnosis with median value 9.7% as the cut-off level or as a continuous variable had no prognostic significance for 2-yr survival. CONCLUSIONS: The sensitivity of WT1 as a MRD marker was low due to the relatively high background WT1 gene expression in BM cells at remission and in subjects without haematological malignancies. Therefore, WT1 gene expression analysis would be beneficial only in those patients who do not have a more specific and sensitive MRD marker.

Long-term outcome of intensive chemotherapy for adults with de novo acute myeloid leukaemia (AML): the nationwide AML-92 study by the Finnish Leukaemia Group.

OBJECTIVE: To investigate the long-term outcome of idarubicin- and cytarabine-based intensive chemotherapy in adult acute myeloid leukaemia (AML). PATIENTS AND METHODS: A total of 327 consecutive patients with de novo AML (promyelocytic leukaemia excluded) aged 16-65 yr were recruited into the study between September 1992 and December 2001. The latest follow-up data were collected in October 2006. After remission achievement with the first (conventional cytarabine) or second (high-dose cytarabine) chemotherapy cycle, three intensive consolidation courses each containing high- or intermediate-dose cytarabine were given. RESULTS: A total of 268 patients (82%) achieved complete remission (CR). CR rate was 82% and 84% for patients <60 and > or =60 yr of age, respectively. CR rates in patients with favourable (93%) and intermediate/normal karyotypes (87%) were significantly (P < 0.01) higher than CR rate in patients with adverse karyotype (61%). Median relapse-free survival (RFS) for the patients not transplanted in the first CR (n = 195) was 1.7 yr (95% CI: 0.81-2.60). At 4 yr, a plateau of 70% in RFS was reached for patients with favourable karyotypes. The 5-yr survival was 71%, 47% and 37% for the non-transplanted patients (n = 202) with favourable, intermediate/normal and intermediate/abnormal karyotypes, respectively, while only 8% of the patients having adverse karyotype were alive at 5 yr (P < 0.01). Of the patients with favourable, intermediate/normal or intermediate/abnormal karyotypes, respectively, 58%, 41% and 31% were expected to be alive at 10 yr. CONCLUSIONS: Idarubicin- and cytarabine-based intensive chemotherapy regimen is very effective in de novo AML for adult patients up to 65 yr of age. New treatment strategies are needed, however, to improve the outcome of the patients with intermediate and adverse karyotypes.

Renal impairment compromises the use of total homocysteine and methylmalonic acid but not total vitamin B12 and holotranscobalamin in screening for vitamin B12 deficiency in the aged.

BACKGROUND: Vitamin B(12) deficiency and renal impairment are common in the aged, and therefore the screening test for vitamin B(12) deficiency should not be affected by renal function. Renal impairment has been associated with increased concentrations of plasma total homocysteine and methylmalonic acid, as well as increased total vitamin B(12) and holotranscobalamin concentrations. METHODS: The effect of renal impairment on vitamin B(12)-related biochemical variables was assessed in 1011 aged subjects. RESULTS: Renal function as indicated by serum cystatin C correlated strongly with plasma total homocysteine (r(s)=0.53, p<0.001) and serum methylmalonic acid (r(s)=0.27, p<0.001), but not with serum total vitamin B(12) (r(s)=-0.04, p=0.227) or holotranscobalamin (r(s)=-0.01, p=0.817). CONCLUSIONS: Either total vitamin B(12) or holotranscobalamin rather than homocysteine or methylmalonic acid should be used when screening an aged population prone to renal impairment.

Vitamin B12 deficiency in the aged: a population-based study.

BACKGROUND: vitamin B12 deficiency is common in the aged, but it is controversial whether only some risk groups should be investigated instead of screening the entire aged population. OBJECTIVES: to describe the prevalence of vitamin B12 deficiency in the Finnish aged, and to find out if the subjects especially prone to vitamin B12 deficiency could be identified by the risk factors or clinical correlates. DESIGN: a cross-sectional, population-based study of 1048 aged subjects (age 65-100 years) was carried out. Data on lifestyle factors and clinical conditions were collected, physical examinations were conducted and laboratory variables related to vitamin B12 were measured. RESULTS: vitamin B12 deficiency had been previously diagnosed in 27 (2.6%) subjects, and a laboratory diagnosis (total vitamin B12 <150 pmol/l, or total vitamin B12 150-250 pmol/l and holotranscobalamin < or =37 pmol/l and homocysteine > or =15 micromol/l) was made for 97 (9.5%) subjects. Low serum total vitamin B12 (<150 pmol/l) was observed in 6.1% and borderline total vitamin B12 (150-250 pmol/l) in 32% of the subjects. Male gender (OR 1.9, 95% CI 1.2-2.9), age > or =75 (OR 2.2, 95% CI 1.4-3.4) and refraining from milk products (OR 2.3, 95% CI 1.2-4.4) increased the probability for vitamin B12 deficiency. Anaemia (OR 1.3, 95% CI 0.7-2.3) or macrocytosis (OR 1.2, 95% CI 0.6-2.7) did not predict vitamin B12 deficiency. CONCLUSION: undiagnosed vitamin B12 deficiency is remarkably common in the aged, but no specific risk group for screening can be identified. Thus, biochemical screening of unselected aged population is justified. General practitioners play a key role in diagnosing early vitamin B12 deficiency.