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Age-race subgroup compared with renin profile as predictors of blood pressure response to antihypertensive therapy. Department of Veterans Affairs Cooperative Study Group on Antihypertensive Agents.

CONTEXT: Renin profiling and age-race subgroup may help select single-drug therapy for stage 1 and stage 2 hypertension. OBJECTIVE: To compare the plasma renin profiling and age-race subgroup methods as predictors of response to single-drug therapy in men with stage 1 and 2 hypertension as defined by the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure. DESIGN: The Veterans Affairs Cooperative Study on Single-Drug Therapy of Hypertension, a randomized controlled trial. SETTING: Fifteen Veterans Affairs hypertension centers. PATIENTS: A total of 1105 ambulatory men with entry diastolic blood pressure (DBP) of 95 to 109 mm Hg, of whom 1031 had valid plasma and urine samples for renin profiling. INTERVENTIONS: Randomization to 1 of 6 antihypertensive drugs: hydrochlorothiazide, atenolol, captopril, clonidine, diltiazem (sustained release), or prazosin. MAIN OUTCOME MEASURE: Treatment response as assessed by percentage achieving goal DBP (<90 mm Hg) in response to a single drug that corresponded to patients' renin profile vs a single drug that corresponded to patients' age-race subgroup. RESULTS: Clonidine and diltiazem had consistent response rates regardless of renin profile (76%, 67%, and 80% for low, medium, and high renin, respectively, for clonidine and 83%, 82%, and 83%, respectively, for diltiazem for patients with baseline DBP of 95-99 mm Hg). Hydrochlorothiazide and prazosin were best in low- and medium-renin profiles; captopril was best in medium- and high-renin profiles (low-, medium-, and high-renin response rates were 82%, 78%, and 14%, respectively, for hydrochlorothiazide; 88%, 67%, and 40%, respectively, for prazosin; and 51%, 83%, and 100%, respectively, for captopril for patients with baseline DBP of 95-99 mm Hg). Response rates for patients with baseline DBP of 95 to 99 mm Hg by age-race subgroup ranged from 70% for clonidine to 90% for prazosin for younger black men, from 50% for captopril to 97% for diltiazem for older black men, from 70% for hydrochlorothiazide to 92% for atenolol for younger white men, and from 84% for hydrochlorothiazide to 95% for diltiazem for older white men. Patients with a correct treatment for their renin profile but incorrect for age-race subgroup had a response rate of 58.7%; patients with an incorrect treatment for their renin profile but correct for age-race subgroup had a response rate of 63.1% (P = .30). After controlling for DBP and interactions with treatment group, age-race subgroup (P<.001) significantly predicted response to single-drug therapy, whereas renin profile was of borderline significance (P= .05). CONCLUSIONS: In these men with stage 1 and stage 2 hypertension, therapeutic responses were consistent with baseline renin profile, but age-race subgroup was a better predictor of response.

Adult↗

A distinct distribution of natural killer cell subgroups in human tissues and blood.

Natural killer (NK) cells have been subdivided according to their CD16/CD56 expression into at least 2 subgroups. We examined the distribution of these NK subgroups in humans. In the blood of normal individuals, CD16++/CD56+/CD3- NK cells predominate, constituting more than 90% of all NK cells. In contrast, decidua is infiltrated almost exclusively by CD16(+/-)/CD56+/CD3- NK cells (>90%), a fact so far seen in context with decidua being an immunoprivileged tissue. However, this NK subgroup can also be detected in the blood, where it comprises about 10% of NK cells. We have found that normal (colon) as well as neoplastic (ovarian and urothelial carcinoma) tissues are also predominantly infiltrated by this CD16+/- NK subgroup. Lymphatic fluid draining solid tissues contains CD16+/- NK cells exclusively, with absolute numbers of NK cells being very low. No predominating NK subgroup was seen in ascites. CD16+/- NK cells, when tested against the target cell lines K562 and JAR, revealed a cytotoxic spectrum different from CD16++ NK cells and from T cells. A change in the CD16/CD56/CD3 phenotype was not seen in either subgroup in long-term cultures containing IL-2 (1,000 U/ml). Our data indicate that the decidua is not the only solid tissue infiltrated by CD16+/- NK cells. Other normal and malignant tissues were also infiltrated predominantly by this NK cell subgroup. We suggest that CD16+/- NK cells represent a functionally distinct NK subgroup involved in the surveillance of solid tissues.

Body Fluids↗

Definition of the human immunoglobulin variable lambda (IGLV) gene subgroups.

Comparison of 60 human immunoglobulin variable lambda (IGLV) sequences allowed us to define seven subgroups designated V lambda I to V lambda VII. We demonstrate that all lambda proteins sequenced so far fall into the subgroups I, II, III and VI, and that the lambda regions previously assigned to subgroups IV and V belong, in fact, to subgroups III and II, respectively. Four sequences not belonging to any of the subgroups I, II, III and VI define the new subgroups IV, V and VII. Interestingly, these subgroups show a higher homology to rabbit or mouse V lambda genes than to the other human V lambda subgroups. By comparison of the proteins either with the sequences deduced from the germ-line genes or with the consensus sequences, the rate of amino acid changes due to somatic mutations or allelic variations was evaluated in several lambda proteins. Framework and complementarity-determining regions of the human IGLV genes and proteins were delineated. Alignment of the lambda sequences shows that functional V-J rearrangement occurs, with or without deletion of nucleotides encoding one or two amino acids at the 3' end of the V gene. Diversity of the third complementarity-determining region is due to somatic mutations and to flexible V-J junction, but there is no evidence of N-diversity in the human lambda locus.

Alleles↗

Tree-based recursive partitioning methods for subdividing sibpairs into relatively more homogeneous subgroups.

We propose a new splitting rule for recursively partitioning sibpair data into relatively more homogeneous subgroups. This strategy is designed to identify subgroups of sibpairs such that within-subgroup analyses result in increased power to detect linkage using Haseman-Elston regression. We assume that the subgroups can be defined by patterns of non-genetic binary covariates measured on each sibpair. The data we consider consists of the squared difference of a quantitative trait measurement on each sibpair, estimates of identity-by-descent (IBD) values at each genetic marker, and binary covariate data describing characteristics of the sibpair (e.g., race, sex, family history of disease). To test the efficacy of this method in linkage analysis, we performed two simulation experiments. In the first, we simulated a mixture consisting of 66.6% of the sibpairs with no linkage and 33.3% of the sibpairs with genetic linkage to one marker. The two groups were distinguished by the value of a single binary covariate. We also simulated one unlinked marker and one random covariate to include as noise in the data. In the second experiment, we simulated a mixture consisting of 55% of the sibpairs with no genetic linkage, 22.5% of the sibpairs with genetic linkage to one marker, and 22.5% of the sibpairs with linkage to a different marker. Each subgroup was defined by a distinct pattern of two binary covariates. We also simulated one unlinked marker and two random covariates to include as noise in the data. Our simulation studies found that we can significantly increase the overall power to detect linkage by fitting Haseman-Elston regression models to homogeneous subgroups with only a small increase in the false-positive rate. Second, the splitting rule can correctly identify important covariates and linked markers. Third, recursive partitioning of sibpair data using this splitting rule can correctly identify sibpair subgroups. These results indicate that partitioning sibpairs into homogeneous subgroups is feasible and significantly increases the power to detect linkage, thus demonstrating the practical utility and potential this new methodology holds.

Chromosome Mapping↗

Preferential expression of human lambda-light-chain variable-region subgroups in multiple myeloma, AL amyloidosis, and Waldenström's macroglobulinemia.

We have compared the distribution of lambda-light-chain variable-region (V lambda) subgroups among Ig lambda molecules found in the serum of normal individuals with that of monoclonal Ig lambda components obtained from patients with plasma cell and related immunoproliferative disorders. A panel of monoclonal antibodies specific for each of the major human V lambda subgroups--V lambda I, V lambda II, V lambda III, V lambda IV, V lambda VI, and V lambda VIII--was used in a highly sensitive enzyme-linked immunosorbent assay (ELISA) to quantitate each of these populations. The mean distribution of Ig lambda I, Ig lambda II, Ig lambda III, Ig lambda IV, Ig lambda VI, and Ig lambda VIII molecules in serum specimens collected from 20 normal adults was approximately 40, 3, 43, 5, 5, and 3% of the total Ig lambda population, respectively. In contrast, that of monoclonal IgG, IgA, and IgD proteins and Bence Jones proteins obtained from patients with multiple myeloma and related gammopathies (n = 196) was approximately 27, 28, 39, 5, 0, and 1%, respectively. The percentage of monoclonal Ig lambda II components found in individuals with AL lambda amyloidosis (n = 41) was comparably increased to that seen in multiple myeloma and was even higher in patients with Waldenström's macroglobulinemia (n = 16), in whom 63% of the IgM lambda proteins were of the V lambda II subgroup. Also evidenced were differences in the distribution of other V lambda subgroups in the disease states: Most striking was the predominance (41%) of the V lambda VI subgroup among monoclonal lambda chains obtained from patients with AL amyloidosis and that this subgroup was found exclusively on amyloidosis-associated proteins. No Ig lambda VI-type myeloma- or macroglobulinemia-related proteins were identified. The observed alterations in V lambda subgroup distribution among "pathologic" monoclonal Igs were attributed to the particular disease and not related to the heavy-chain class. Our finding that certain V lambda subgroups are nonstochastically expressed in lambda-type multiple myeloma, AL amyloidosis, and Waldenström's macroglobulinemia provides evidence for abnormal VL gene usage in these disorders and, thus, furnishes new insight into their pathogenesis.

Amyloid↗

Identification of several functional subgroups of HLA-B27 by restriction of the activity of antiviral T killer lymphocytes.

Anti-Epstein-Barr virus and antiinfluenza A cytotoxic T lymphocytes (CTL) have been used to study the restriction of human antiviral responses by HLA-B27 antigens. Three functional subgroups of HLA-B27 have been clearly distinguished by this "restriction-typing assay". No cross-reaction could be detected between the three subgroups either at the CTL level or at the level of antigen-presenting cells. The cells of subgroup 1 are always positive [M2(+)] when tested in immunofluorescence with a monoclonal B27-specific antibody which divides HLA-B27 into a major M2(+) and a minor M2(-) subgroup. These M2(+) group 1 cells are apparently also HLA-B27W as previously shown by Ivanyi and co-workers using anti-HLA-CTL. Subgroup 2 includes only M2(-) cells. A comparison between this group and the previously described HLA-B27K is not fully conclusive, since two typing cells which were clearly HLA-B27K apparently did not belong to group 2. Only two donors, both of Oriental origin, have been included in subgroup 3. Both of them were "M2 intermediate". These results demonstrate (1) the existence of several functional subgroups of HLA-B27 with an interesting correlation with the M2(+), M2(-), or M2 intermediate phenotypes, and (2) the possibility of using the restriction-typing assay to define such functional subgroups not detected by classical allosera.

Antibodies, Monoclonal↗

Subgrouping of human rotavirus strains by complement fixation, indirect double-antibody sandwich enzyme-linked immunosorbent assay and solid-phase immune electron microscopy.

Complement fixation (CF), indirect double-antibody sandwich (DAS) enzyme-linked immunosorbent assay (ELISA) and solid-phase immune electron microscopy (SPIEM) were compared for their ability to subgroup 73 human rotavirus (HRV) strains from infants and young children with gastroenteritis admitted to one or the other of two different hospitals of Northern Italy. By both indirect DAS ELISA and SPIEM all 73 HRV strains were classified into one or the other of two subgroups. By CF only 67 strains could be subgrouped, as six HRV-positive stools showed anticomplementary activity which could not be eliminated. Indirect DAS ELISA required subgroup-specific, unabsorbed antisera from two different animal species. For SPIEM two antisera from a single animal species were needed, but they had to be absorbed with single-shelled bovine rotavirus for HRV subgrouping to be reliable. Indirect DAS ELISA appeared to be the technique most suitable for extensive application in epidemiological studies of HRV infections by different subgroups. However, SPIEM allowed rapid subgrouping of HRV in stool specimens showing anticomplementary activity in the CF test or non-specific reactions in the ELISA test. In one area of Northern Italy the prevalence of subgroup I HRV infections was 7.8 per cent, while in another it reached 68.1 per cent in the same period.

Antigens, Viral↗

Positive selection on nucleotide substitutions and indels in accessory gland proteins of the Drosophila pseudoobscura subgroup.

Genes encoding reproductive proteins often diverge rapidly due to positive selection on nucleotide substitutions. While this general pattern is well established, the extent to which specific reproductive genes experience similar selection in different clades has been little explored, nor have possible targets of positive selection other than nucleotide substitutions, such as indels, received much attention. Here, we inspect for the signature of positive selection in the genes encoding five accessory gland proteins (Acps) (Acp26Aa, Acp32CD, Acp53Ea, Acp62F, and Acp70A) originally described from Drosophila melanogaster but with recognizable orthologues in the D. pseudoobscura subgroup. We compare patterns of selection within the D. psuedoobscura subgroup to those in the D. melanogaster subgroup. Similar patterns of positive selection were found in Acp26Aa and Acp62F in the two subgroups, while Acp53Ea and Acp70A experienced purifying selection in both subgroups. These proteins have thus remained targets for similar types of selection over long (>21-MY) periods of time. We also found several indel substitutions and polymorphisms in Acp26Aa and Acp32CD. These indels occur in the same regions as positively selected nucleotide substitutions for Acp26Aa in the D. pseudoobscura subgroup but not in the D. melanogaster subgroup. Rates of indel substitution within Acp26Aa in the D. pseudoobscura subgroup were up to several times those in noncoding regions of the Drosophila genome. This suggests that indel substitutions may be under positive selection and may play a key role in the divergence of some Acps.

Amino Acid Sequence↗

Identification of three new bovine T-cell receptor delta variable gene subgroups expressed by peripheral blood T cells.

To understand the biology of gammadelta T cells in ruminants, it is necessary to have a comprehensive picture of gammadelta T-cell receptor gene diversity and expression. In this study, three new subgroups of bovine T-cell receptor delta (TRD) variable genes were identified by RT-PCR and sequencing and homology with TRDV genes from other mammals determined. Previously unidentified TRDV subgroup genes described in this study include the bovine homologues of ovine TRDV2, TRDV3, and TRDV4 which were named accordingly. TRDV2 subgroup has two genes (TRDV2-1 and TRDV2-2) while we found the previously identified TRDV1 has at least eight genes corresponding to separate genomic sequences. Nucleotide and amino acid sequences for particular gene subgroups between cattle and sheep were more than 87% identical but identities among TRDV subgroups within a species were much less, with bovine TRDV4 having <45% identity to the other three bovine TRDV gene subgroups. Analysis of circulating bovine gammadelta T cells revealed that genes from all four TRDV subgroups were expressed in combination with TRDJ1, TRDJ3, and TRDC, although TRDV4 was the least represented, and all displayed a variety of CDR3 junctional lengths. Finally, some genes within the TRDV1, TRDV2, and TRDV3 subgroups recombined with TRAV incorporating TRAJs, suggesting dual use.

Amino Acid Sequence↗

Placenta previa--the identification of low- and high-risk subgroups.

Among a group of 155 women with placenta previa (PP), two subgroups were identified: subgroup A consisted of 56 pregnancies (56 newborns) in women who had an asymptomatic antenatal course and who were delivered following a single episode of uterine bleeding; subgroup B consisted of 99 pregnancies (103 newborns) in women who had multiple antepartum bleeding episodes. The women in subgroup B were older, more parous, had more abortions and caesarean sections compared to those in subgroup A. Although the distribution of women in both subgroups with respect to the types of PP was similar, the prognosis in subgroup A was better with respect to various maternal and perinatal aspects. The recognition of low- and high-risk subgroups among women with PP may have practical implications for management protocols.

Abortion, Spontaneous↗

Analysis of clinical trial outcomes: alternative approaches to subgroup analysis.

Subgroup analysis is understood as the investigation of the influence of factors other than treatment factors on the response variables or treatment effects in clinical trials. Usual techniques are the Mantel-Haenszel technique and regression technique. The Mantel-Haenszel technique combines (pools) treatment effects (expressed by relative odds) in different subgroups to an "overall" effect. This is meaningful if all subgroups have the same treatment effects. In general, however, there will be interactions between treatment and subgroups and the Mantel-Haenszel estimates will be misleading. Regression models allow analysis of interactions if the interactions are modeled by product terms. If there are many subgroup factors the number of product terms necessary for an adequate modeling of the interactions may be higher than the number of observations and an analysis of the interactions is impossible. To overcome these difficulties as an alternative approach the "classification tree" technique is proposed. This technique combines the possible subgroup constellations to subgroup clusters with homogeneous response within the cluster. From the distribution of the subgroup constellation to the different clusters inferences about the interaction structure can be obtained. The technique is demonstrated with an example of a long-term clinical trial.

Cluster Analysis↗

Behavioral assessment of low back pain: identification of pain behavior subgroups.

A hierarchical cluster analysis procedure was used to identify homogeneous subgroups of low back pain patients who show similar pain behavior patterns during a videotaped behavior sample. Subjects, 106 chronic low back pain patients, were divided into 2 samples. The cluster analysis procedure identified 4 very similar subgroups in sample 1 and sample 2. The first subgroup showed a low or moderate level of guarding and a low level of other pain behaviors. The second subgroup showed a high level of guarding and a moderate level of rubbing of the painful area. The third subgroup showed high levels of guarding and moderate levels of bracing and rubbing. The fourth subgroup exhibited a very high level of rubbing and moderate levels of bracing. The subgroups identified may require somewhat different approaches to pain assessment and treatment. The results of this study suggest that the variability in pain behavior evident in low back pain populations may be due to the fact that within these populations there are homogeneous subgroups of patients who differ in the motor pain behaviors they display.

Adult↗

Assessment of left atrial appendage function by biplane transesophageal echocardiography in patients with nonrheumatic atrial fibrillation: identification of a subgroup of patients at increased embolic risk.

OBJECTIVES: This study was conducted to identify a subgroup of patients with nonrheumatic atrial fibrillation with an increased risk for cardiogenic embolism by assessing left atrial appendage function. BACKGROUND: Patients with nonrheumatic atrial fibrillation have an increased risk for thromboembolic complications. The left atrial appendage is the most likely source for thrombus formation. It is likely that the appendage function (contraction, filling dynamics) is related to the pathogenesis of thrombus formation. METHODS: Twenty-nine patients with nonrheumatic atrial fibrillation (group I) underwent biplane transesophageal echocardiography. The maximal and minimal areas during a cardiac cycle and the peak emptying and filling velocities of the appendage were measured in both scan planes. For comparison, two additional groups were also analyzed. Group II consisted of 12 patients with chronic atrial fibrillation due to significant mitral stenosis, and group III consisted of 30 patients who were in sinus rhythm. RESULTS: Patients with nonrheumatic atrial fibrillation showed two distinct appendage flow patterns: either well defined peak filling and emptying waves (> or = 25 cm/s) with visible fibrillatory contractions of the appendage wall ("high flow profile") or irregular, very low, peak filling and emptying waves (< 25 cm/s) associated with almost no visible appendage contractions ("low flow profile"). The left atrial appendage function in the first subgroup resembles that seen in patients with sinus rhythm, whereas the appendage function in the latter subgroup resembles more the "static pouch" seen in patients with rheumatic atrial fibrillation. Events suggestive of cardiogenic embolism occurred in six patients from group I, five of whom were in the low flow profile subgroup (p < 0.05). The spontaneous echo contrast phenomenon was observed in 80% of the low flow profile subgroup but in only 5% in the high flow profile subgroup (p < 0.05). Three thrombi confined to the left atrial appendage were detected by transesophageal echocardiography in group I; all three of the patients were in the low flow profile subgroup. CONCLUSIONS: The assessment of left atrial appendage function by transesophageal echocardiography may be helpful to identify subgroups of patients with nonrheumatic atrial fibrillation with an increased risk of thrombus formation.

Atrial Fibrillation↗

Musculoskeletal pain in primary health care: subgroups based on pain intensity, disability, self-efficacy, and fear-avoidance variables.

UNLABELLED: The purpose of this study was to identify and describe subgroup profiles based on self-reported pain intensity, disability, self-efficacy, fear of movement/(re)injury, and catastrophizing in patients with musculoskeletal pain. Two primary health care samples (n = 215 and n = 161) were used. Self-report questionnaires were completed at the start of physical therapy treatment. Cluster analysis was used to generate subgroups. Three subgroups were identified in sample 1 and replicated in sample 2. These were labeled "High self-efficacy-Low fear-avoidance," "Low self-efficacy-Low fear-avoidance," and "Low self-efficacy-High fear-avoidance." The subgroups differed significantly in work-status in both samples (P < .001), but not in age, gender, or duration of pain. The results show the presence of subgroups based on pain intensity, disability, self-efficacy, fear of movement/(re)injury, and catastrophizing. The profile patterns suggest that different management strategies may be relevant in each subgroup. PERSPECTIVE: This article presents subgroups of patients with musculoskeletal pain with different profiles in pain intensity, disability, and psychosocial variables possible to modify by physical therapy management. The results could potentially aid clinicians in tailoring assessment and treatment approaches to each subgroup.

Adult↗

Amino acid residues Tyr-67, Asn-72, and Asp-73 of the TVB receptor are important for subgroup E avian sarcoma and leukosis virus interaction.

The chicken TVB(S1) protein serves as the cellular receptor for the cytopathic subgroups B and D avian sarcoma and leukosis viruses (ASLVs) as well as for the non-cytopathic subgroup E ASLV. Previous studies had mapped the subgroup B viral interaction determinants to a region that was located between residues 32 and 46 of TVB(S1) [J. Virol. 76 (2002) 5404]. To gain a greater insight into ASLV Env-receptor interactions and the possible role of these interactions in viral cytopathic effects, we employed a homolog-scanning mutagenesis approach to identify amino acid residues important for subgroup E viral receptor function by exchanging amino acid residues between TVB(S1) and its human homolog, DR5. These studies identified residues Tyr-67, Asn-72, and Asp-73 of TVB(S1) as important subgroup E viral interaction determinants. Intriguingly, these three residues are conserved between TVB(S1) and DR5, demonstrating that the human protein contains critical subgroup E viral interaction determinants, but in this context, they cannot support viral entry. These data confirm that the molecular determinants of the TVB receptor required for subgroup E viral entry are completely distinct from those used by subgroup B viruses.

Amino Acid Sequence↗

Epidemiology of rotavirus subgroups and serotypes in Belem, Brazil: a three-year study.

Rotavirus subgroups and serotypes were determined in 61 rotavirus-positive faecal samples obtained from children living in Belém, Brazil, followed up from birth to 3 years of age. Fifty-five (90%) of the specimens were subgrouped and the serotypes of 30 (49%) of them were determined. Subgroup II was detected in 49 (89%) of the 55 subgrouped strains. Serotype 1 was present in 15 (50%) of the 30 serotyped samples; serotypes 2, 3 and 4 were found in 30%, 3.3% and 16.7% respectively, of these specimens. Absence of Vp7, the major outer capsid glycoprotein, did not allow serotyping in 21 (34.4%) of the 61 rotavirus-positive specimens, and an unidentifiable new serotype was found in faeces of one child. In addition, 4 samples were classified as subgroup II serotype 2 (which is very unusual). Twelve (80%) of the 15 serotype 1 (subgroup II) specimens were collected from children (5 of them asymptomatic) during their first year of life. All 9 serotype 2 (subgroups I, II, or not determined) samples were detected during the second and third years of life, 7 (77.8%) of them were related to apparent infections. The 5 serotype 4 (subgroup II) samples were obtained throughout the study period, and were associated with both symptomatic (3 cases) and asymptomatic infections. Thirteen children had more than 1 rotavirus infection. Three had 3 successive infections. In 3 cases, the initial infection (either symptomatic or asymptomatic) caused by serotype 1, was followed by a subsequent diarrhoeic episode associated with serotype 2.

Age Factors↗

Pain-related correlates of MMPI profile subgroups among back pain patients.

The MMPI profiles of 96 male and 218 female patients attending a back pain clinic in a private university-affiliated, orthopedic hospital were analyzed by a hierarchical clustering procedure. The clustering procedure produced four male and four female profile subgroups. The subgroups were compared with one another on the basis of patients' responses to the Cornell Medical Index and revised McGill Pain Assessment Questionnaire. Within the male and female patient cohorts it was found that profile subgroups featuring elevated clinical scales showed greater disruptions of daily activities than did subgroups with relatively unelevated profiles. However, profile subgroups with elevations primarily on the neurotic triad scales reported greater affective disturbance and disruption of daily activities than did subgroups with elevations on both the neurotic triad and relatively psychotic scales. In addition, profile subgroups with subclinical elevations on the neurotic triad scales appeared to have adjusted to their pain experience more poorly than did subgroups that featured scores on nearly all clinical scales that were within one standard deviation of the mean. Suggestions are provided for the use of the MMPI in assessing chronic pain patients and future research regarding cluster analyses of patients' MMPI profiles.

Adolescent↗

Musculoskeletal status and disability of MMPI profile subgroups among patients with low back pain.

The Minnesota Multiphasic Personality Inventory (MMPI) profiles of 205 male and 157 female patients with acute and chronic low back pain (LBP) were studied for replicable homogeneous subgroups using three cluster-analysis procedures. Two normal and three clinically elevated profile subgroups were identified. The two normal subgroups were characterized by relatively normal musculoskeletal condition and were least disabled, but they differed somewhat from each other in duration of pain, presence of physical abnormalities, and daily functioning. The third subgroup had the following characteristics: an elevated neurotic triad, greatest duration of symptoms, most abnormal physical findings, greatest limitation of motion, most pain complaints during physical examination, and the fewest number of intact functional activities. The fourth subgroup, with an elevated neurotic triad plus subclinical elevations on other scales, had somewhat less musculoskeletal impairment but had extensive work disability, financial compensation, and previous surgeries. The fifth and most pathologic profile subgroup surprisingly consisted largely of acute-pain patients whose musculoskeletal condition and daily functioning were similar to those of the normal subgroups. Patients in the three abnormal MMPI subgroups were exposed to more LBP physical-risk factors in the workplace. Implications for psychological treatment with these different profile types are discussed.

Adolescent↗